ows designing

Download Ows Designing

Post on 04-Jun-2018

215 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • 8/13/2019 Ows Designing

    1/43

    Approved for public release; distribution is unlimited.

    ERDC/CERL

    TR-00-40

    Designing Coalescing Oil/Water Separators

    for Use at Army Washracks

    Constructi

    on

    Engineerin

    g

    ResearchL

    aboratory

    by Gary L. Gerdes, Angelo DeGuzman,

    and Jeffrey GrubichDecember 200

  • 8/13/2019 Ows Designing

    2/43

    2 ERDC/CERL TR-00-40

    Foreword

    This study was conducted for the U.S. Army Corps of Engineers under project

    40162720A896, Base Facilities Environmental Quality, Work Unit TB0, Oil/

    Wa ter S epar a tor Technology. The technical monitor wa s Gr egory W. Hugh es

    (CECW-EW).

    The w ork wa s performed by the E nvironmenta l P rocesses B ra nch (CN-E) of th e

    Installations Division (CN), Construction Engineering Research Laboratory(CE RL). The CE RL P rincipal Investiga tor w a s G a ry L. G erdes, CN-E. The

    technical editor w a s Linda L. Whea tley, In forma tion Techn ology La bora tory. Dr.

    Ilker R. Adiguzel is Chief, CN-E, a nd D r. J ohn T. B a ndy is Chief, CN. The asso-

    ciat ed Techn ica l Director w a s G a ry W. Scha nche, CVT. The Acting D irector of

    CE RL is William D . G oran.

    CE RL is an element of the U.S . Army En gineer Research a nd D evelopment Cen-

    ter (ERDC ), U .S. Army C orps of En gineers. The Director of ER DC is D r. J a mes

    R. Houston a nd t he Comman der is COL J a mes S. Weller.

    DISCLAIMERDISCLAIMERDISCLAIMERDISCLAIMER

    The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names

    does not constitute an official endorsement or approval of the use of such commercial products. All product names and

    trademarks cited are the property of their respective owners.

    The findings of this report are not to be construed as an official Department of the Army position unless so designated by

    other authorized documents.

    DESTROY THIS REPORT WHEN IT IS NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.DESTROY THIS REPORT WHEN IT IS NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.DESTROY THIS REPORT WHEN IT IS NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.DESTROY THIS REPORT WHEN IT IS NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.

  • 8/13/2019 Ows Designing

    3/43

    ERDC/CERL TR-00-40 3

    Contents

    Foreword............................................................................................................................................... 2

    List of Figures and Tables.................................................................................................................. 5

    1 Introduction................................................................................................................................... 7

    Background ......................................................................................................................... 7

    Objectives .........................................................................................................................10

    Approach........................................................................................................................... 10Mode of Technology Transfer............................................................................................ 11

    Units of Weight and Measure............................................................................................ 11

    2 Wash Water Characterization................................................................................................... 12

    U.S. Army Reserve Study .................................................................................................12

    Influent Characterization: All Facilities ........................................................................................12

    Aviation Support Facilities............................................................................................................13

    Area Maintenance Support Activities ...........................................................................................14

    Equipment Concentration Sites ...................................................................................................14

    Organizational Maintenance Shops .............................................................................................14Other Sites...................................................................................................................................15

    Summary...........................................................................................................................16

    3 Treatability Study........................................................................................................................ 17

    Experiment Design............................................................................................................17

    Contaminants...............................................................................................................................18

    Coalescer Material.......................................................................................................................18

    Coalescing Plate Angle of Incline.................................................................................................19

    Water Temperature ......................................................................................................................19

    Configurations..............................................................................................................................19

    Duration .......................................................................................................................................20

    Surface Loading Rate ..................................................................................................................20

    Sampling and Analysis.................................................................................................................21

    Test Start-up.................................................................................................................................21

    Results ..............................................................................................................................21

    Oil and Grease Removal..............................................................................................................21

    Sediment Accumulation ...............................................................................................................22

  • 8/13/2019 Ows Designing

    4/43

    4 ERDC/CERL TR-00-40

    4 Conclusions and Recommendations..................................................................................... 23

    Conclusions.......................................................................................................................23

    Recommendations ............................................................................................................ 23

    References.......................................................................................................................................... 24

    Appendix: Results of Test Cell Sampling..................................................................................... 25

    CERL Distribution.............................................................................................................................. 42

    Report Documentation Page........................................................................................................... 43

  • 8/13/2019 Ows Designing

    5/43

    ERDC/CERL TR-00-40 5

    List of Figures and Tables

    Figures

    1 Oil and soil particle movement between parallel coalescer plates .......................8

    2 Eight test cells operating in parallel .................................................................... 17

    3 Coalescer configurations ....................................................................................20

    A1 Polypropylene 45 degrees downward flow: TSS at surface loading rate of

    0.37 gpm/ft2.........................................................................................................25

    A2 Polypropylene 45 degrees downward flow: O&G at surface loading rate of

    0.37 gpm/ft2.........................................................................................................26

    A3 Polypropylene 60 degrees downward flow: TSS at surface loading rate of

    0.37 gpm/ft2.........................................................................................................26

    A4 Polypropylene 60 degrees downward flow: O&G at surface loading rate of

    0.37 gpm/ft2.........................................................................................................27

    A5 Polypropylene 90 degrees horizontal flow: TSS at surface loading rate of

    0.37 gpm/ft2.........................................................................................................27

    A6 Polypropylene 90 degrees horizontal flow: O&G at surface loading rate of

    0.37 gpm/ft2.........................................................................................................28

    A7 Polypropylene 45 degrees horizontal flow: TSS at surface loading rate of

    0.37 gpm/ft2.........................................................................................................28

    A8 Polypropylene 45 degrees horizontal flow: O&G at surface loading rate of

    0.37 gpm/ft2.........................................................................................................29

    A9 Polyethylene 45 degrees downward flow: TSS at surface loading rate of

    0.37 gpm/ft2.........................................................................................................29

    A10 Polyethylene 45 degrees downward flow: O&G at surface loading rate of

    0.37 gpm/ft2.........................................................................................................30

    A11 Polyethylene 60 degrees downward flow: TSS at surface loading rate of

    0.37 gpm/ft2.........................................................................................................30

    A12 Polyethylene 60 degrees downward flow: O&G at surface loading rate of0.37 gpm/ft

    2.........................................................................................................31

    A13 Polyethylene 90 degrees horizontal flow: TSS at surface loading rate of

    0.37 gpm/ft2.........................................................................................................31

    A14 Polyethylene 90 degrees horizontal flow: O&G at surface loading rate of

    0.37 gpm/ft2.........................................................................................................32

    A15 Polyethylene 45 degrees horizontal flow: TSS at surface loading rate of

    0.37 gpm/ft2.........................................................................................................32

    A16 Polyethylene 45 degrees horizontal flow: O&G at surface loading rate of

    0.37 gpm/ft2.........................................................................................................33

  • 8/13/2019 Ows Designing

    6/43

    6 ERDC/CERL TR-00-40

    A17 Corrugated angled ribs slanted away from flow: TSS at surface loading

    rate of 0.37 gpm/ft2..............................................................................................33

    A18 Corrugated angled ribs slanted away from flow: O&G at surface loading

    rate of 0.37 gpm/ft2..............................................................................................34

    A19 Corrugated angled ribs slanted toward flow: TSS at surface loading rateof 0.37 gpm/ft

    2.....................................................................................................34

    A20 Corrugated angled ribs slanted toward flow: O&G at surface loading rate

    of 0.37 gpm/ft2.....................................................................................................35

    A21 Corrugated angled ribs slanted away from flow: TSS at surface loading

    rate of 0.25 gpm/ft2..............................................................................................35

    A22 Corrugated angled ribs slanted away from flow: O&G at surface loading

    rate of 0.25 gpm/ft2..............................................................................................36

    A23 Corrugated angled ribs slanted toward flow: TSS at surface loading rate

    of 0.25 gpm/ft2.....................................................................................................36

    A24 Corrugated angled ribs slanted toward flow: O&G at surface loading rateof 0.25 gpm/ft

    2.....................................................................................................37

    A25 Corrugated angled ribs slanted away from flow: TSS at surface loading

    rate of 0.49 gpm/ft2..............................................................................................37

    A26 Corrugated angled ribs slanted away from flow: O&G at surface loading

    rate of 0.49 gpm/ft2..............................................................................................38

    A27 Corrugated angled ribs slanted toward flow: TSS at surface loading rate

    of 0.49 gpm/ft2.....................................................................................................38

    A28 Corrugated angled ribs slanted toward flow: O&G at surface loading rate

    of 0.49 gpm/ft2.....................................................................................................39

    A29 Polypropylene 45 degrees downward flow: TSS at surface loading rate of0.25 gpm/ft2.........................................................................................................39

    A30 Polypropylene 45 degrees downward flow: O&G at surface loading rate of

    0.25 gpm/ft2.........................................................................................................40

    A31 Polypropylene 60 degrees downward flow: TSS at surface loading rate of

    0.25 gpm/ft2.........................................................................................................40

    A32 Polypropylene 60 degrees downward flow: O&G at surface loading rate of

    0.25 gpm/ft2.........................................................................................................41

    Tables

    1 Summary of sampling data from 10 facilities ...................................................... 13

    2 Summary of ASF wash water characterization data ........................................... 13

    3 Summary of AMSA wash water characterization data ........................................14

    4 Summary of ECS wash water characterization data ..........................................14

    5 Summary of OMS wash water characterization data.......................................... 15

  • 8/13/2019 Ows Designing

    7/43

    ERDC/CERL TR-00-40 7

    1 Introduction

    Background

    The U.S . Army h a s thousa nds of oil/wa ter separa tors to trea t w a stewa ter from

    tactical vehicle washracks at active Army, Army Reserve, and Army National

    G ua rd facilities. The va st ma jority of these sepa ra tors are used as pretreat ment

    prior to discharge of wa ste wa sh wa ter into a sa nitar y or industrial sewer. Exist-

    ing Army separators are typically below ground, cast-in-place concrete, simplegra vity-ty pe sepa ra tors. Simple gra vity separ a tors consist of a chamber or

    chambers w here the velocity of wa stewa ter slows enough to a llow free oil to rise

    to th e sur fa ce. Ca st-in-place concrete sepa ra tors, however, a re seldom con-

    st ruct ed a nym ore, an d designer s now specify/inst a ll off-th e-shelf oil/w a ter sepa-

    ra tors. Most off-the-shelf separa tors being insta lled currently a re coalescing-

    type gra vity separa tors. Fa cility designers choose coalescing separ a tors beca use

    they are smaller, less expensive, and require less site work than the equivalent

    simple gravity separa tors. Many ma nufacturers now offer a boveground separ a-

    tors th a t a re significant ly less expensive to inst a ll .

    Oil/wa ter sepa ra tor ma nufa cturers a lso incorporat e coalescers in t heir designs to

    improve th e performa nce. B eca use coalescing devices short en the dist a nce oil

    par ticles must r ise, oil remova l is quicker a nd ma y occur in a sma ller separa tion

    cha mber. Sm a ll oil par ticles rise to collect on th e surfa ces of th e coalescer, com-

    bine to form la rger globules (coa lesce), a nd migra te to th e wa ter sur face. The

    heavier soil part icles sink to th e lower coa lescer sur fa ce, a nd eventua lly slide to

    th e bott om of the separa tor. Figure 1 shows th e schema tic of part icle movement

    in a simple par a llel-plat e coalescer.

    Coalescers have many configurations, from simple arrays of parallel plates to

    honeycomb meshes. Recent tr ends in coalescer design ar e to ca use many

    cha nges in th e direction of flow a s wa stewa ter winds i ts w ay through the separa -

    tor. The intent is to ca use non-lamina r flow, thus increasing th e probability tha t

    oil droplets w ill collide a nd coa lesce.

  • 8/13/2019 Ows Designing

    8/43

    8 ERDC/CERL TR-00-40

    Figure 1. Oil and soil particle movement between parallel coalescer plates.

    The Corps of E ngin eers E ngin eering Technica l L ett er (E TL) 1110-3-466, Selec-

    tion an d Design of Oil Wa ter S epa ra tors a t Army F a cilities, August 1994, con-

    ta ins some discussion of coalescing sepa ra tors, but little or no da ta wa s a vaila ble

    to support specific design guida nce. The la ck of specific design guida nce ha s led

    to the purcha se of incorrectly sized separa tors at Army insta llations. This wa s

    report ed in P ublic Works Technica l B ullet in (P WTB ) 200-1-05, Oil/Wa t er S epa -

    ra tor Selection, Inst a llation, a nd Ma intena nce: Lessons Lear ned, 5 December

    1997. The P WTB a lso discusses how vendor litera tu re ca n be mislead ing, fur-

    ther reinforcing th e need for design guida nce.

    ETL 1110-3-466 raises concerns that solids in Army wash water will collect in

    th e ga ps betw een coa lescer surfa ces an d plug the separ a tor. To minimize plug-

    ging, it recommends a t least 0.75-in. gaps between surfa ces. B eca use of the

    plugging problem, the ETL also raises concerns regarding the maintenance re-

    quirements for coa lescing separa tors. These concerns a re demonstr a ted a t every

    Army installation by the need for periodic separator cleaning, not for the accu-mula tion of oil but for t he a ccumula tion of sediment.

    The ETL recommend s th a t a ny Arm y oil/w a ter sepa ra tor mu st be easily a ccessi-

    ble for periodic ma int ena nce. This a ccessibility is especia lly crit ical for coalesc-

    ing sepa ra tors. The coa lescer pa ck must be ea sy to remove and ea sy to clean.

    G enerally, only t he pa ra llel-plat e coa lescers a re ea sy t o clea n wit hout completely

    disma nt ling the coa lescer pack. This genera lization wa s confirmed by CERL

    Oleophi l ic m aterial

    surface

    Flow

  • 8/13/2019 Ows Designing

    9/43

    ERDC/CERL TR-00-40 9

    personnel who inspected separators with mesh or vertical mesh tube-type coa-

    lescers. These coalescers seem to eas ily plug w ith vegeta tion debris commonly

    found in Army wa sh wa ter. Only coalescing separa tors with the fla t para llel

    plates ca n be r ecommended for Army use; therefore, they w ere the prima ry focus

    of this st udy.

    Dirt washed off Army vehicles becomes suspended solid particles in the waste

    wa sh wa ter. These par ticles a tt a ch to the oil droplets, thus interfering w ith the

    oil removal ca pa city of the separ a tor. This process is described in th e Corps ETL

    on sepa ra tor design (U SACE 1994) a nd B rincks (1996). It is a lso supported by

    observations of significant amounts of oil in the sediment of Army separators.

    Oil-soil agglomerations have a wide range of specific gravities, but always are

    more dense th a n oil droplets. St okes La w is t ypica lly used to model the sepa ra -

    tion of oil an d w a ter.

    Stokes Law : Vp= 54.48 (

    p-

    w)d

    p

    2 Velocit y (V

    p) is positive if pa rt icle is

    falling; negat ive if rising.

    Stokes La w generally sa ys th a t t he velocity of rise (or fall) of a par ticle in wa ter

    is proport iona l to: the specific gra vity of the par ticle minus 1; the diam eter of

    th e pa rt icle; an d the temperat ure of the wa ter. As the specific gra vity of th e par -

    ticle approaches that of water (usually 1.0), the velocity of the particle ap-

    proaches zero. Therefore, w hen a pa rt icle of oil a tt a ches to a soil pa rt icle, th e

    velocity of rise decreases. If t he soil pa rt icle is la rge enough, th e oil-soil a gglom-erat ion w ill sink.

    For St okes law to be a pplica ble wh en modeling th e oil separa tion from wa stewa -

    ter laden w ith suspended solids, the distr ibution of oil par ticle a nd oil-soil par ti-

    cle diameters a nd specific gra vities must be known. P rior to this stu dy, this dis-

    tr ibution w a s never char a cterized. Therefore, separ a tor performa nce could not

    be predicted for Army w a sh w a ter using St okes Law.

    Ma ny v endors of off-th e-shelf oil/w a ter separ a tors u se St okes law to predict the

    performa nce of their equ ipment for removing free oil. This can only be applica -

    ble for simple mixtu res of free oil droplets in wa ter. Thus , vendor litera tu re ca n

    be mislea ding t o persons responsible for pur chasing sepa ra tors for Army a pplica -

    tions. B eca use Army gu idan ce did not exist, an d vendor guida nce is not a pplica -

    ble, this study wa s conducted so tha t insta l lat ion personnel , as w ell as w ashr ack

    designers, have specific guidance for the selection of off-the-shelf coalescing

    oil/w a ter separ a tors.

  • 8/13/2019 Ows Designing

    10/43

    10 ERDC/CERL TR-00-40

    Objectives

    It w a s th e objective of th is study to develop design guida nce tha t ca n be used by

    Army planners a nd designers w hen inst a lling coalescing-ty pe oil/wa ter sepa ra -

    tors to pretrea t vehicle ma intena nce wa sh wa ter. It w a s also a n objective to

    characterize the oil-soil agglomerations that obviously form during the washing

    process.

    Approach

    The approa ch for this study ha d tw o thr usts: (1) char a cterize Army w a shra ck

    wastewater, and (2) conduct bench-scale treatability studies to match coalescer

    design wit h Army w a sh wa ter. The char a cterizat ion study ha d to be completedbefore ini t iat ing the treat abil ity study. Army w ash w at er wa s recreated in the

    laboratory based on the contaminant loading measured at actual Army wash-

    ra cks. It w a s most import a nt t o know the concentra tions of suspended solids

    a nd gr ease/oil in t he wa ter, since it is t hese conta mina nts tha t a re removed from

    th e w a stew a ter in the oil/w a ter separa tor.

    Wa sh w at er wa s sa mpled a nd a na lyzed from severa l Army w ashr acks, represent-

    ing a va riety of vehicle w a shing scena rios. Cha pter 2 of th is report presents t he

    results of this portion of the study.

    The challenge to chara cterizing t he oil-soil agglomerat ions t ha t form during the

    washing process was that the wash water is a non-homogeneous mixture of oil

    droplets, soil pa rt icles, a nd oil-soil a gglomera tions. A meth od to different ia te

    these components during a par ticle size ana lysis could not be found. In pa rt icu-

    lar, a method t o distinguish oil-soil agglomerat ions of va rious constituent ra tios

    seemed impossible to devise. Furt her, there wa s no gua ra nt ee th a t pa rt icle iden-

    tification techniques would not alter the character of fragile oil-soil agglomera-

    tions during the ana lysis. It w a s concluded tha t cha ra cterizing the par ticle dis-

    tribution of Army w ash wa ter w as n ot pra ctica l , and t ha t t he cha ra cterization ofthe wash water would rely entirely on measuring the concentrations of oil and

    solids. Note: Without par ticle size distr ibution a nd a gglomera tion cha ra cteriza-

    tion dat a, St okes La w cannot be used to predict oil/wa ter sepa ra tor performa nce

    for Army w ash wa ter.

    An a rra y of test cells wa s constructed to conduct t he trea ta bility st udy. The test

    cells were constructed so that several coalescer configurations could be evaluated

    a t t he same time, using a common source of wa stew a ter influent. The concentra -

    tions of oil and solids in the wastewater were set according to the results of the

  • 8/13/2019 Ows Designing

    11/43

    ERDC/CERL TR-00-40 11

    wa sh wa ter sa mpling stud y. Cha pter 3 of th is report discusses the experimenta l

    para meters and test results .

    A performa nce goa l of 100 ppm oil a nd g rea se (O&G ) in t he test cell effluent w a s

    set. This goa l represents a commonly used pretreat ment requirement set by

    ma ny P ublicly Ow ned Trea tm ent Works (P OTW). The success of a given test ing

    scena rio is based on t his performa nce goa l.

    The presence of solids in the wash water affects performance in ways besides

    th eir becoming tied up with th e oil droplets. It w a s also suspected tha t solids

    w ould a ccumu la te on the surfa ce of th e coa lescer. This accumula tion would

    negatively affect performance by narrowing the gap between the coalescer sur-

    faces, thus increasing t he velocity of wa ter t hrough th e coalescer a nd decreasing

    droplet removal. Solids could a lso negat ively a ffect performa nce if they coa tedthe oliophilic coalescer ma teria l, thus diminishing the a va ilable surface on w hich

    th e oil droplets could coa lesce. Ev idence of th ese effects w ould ha ve a bea ring on

    both recommended design an d ma intena nce requirements for coa lescing separa -

    tors.

    Mode of Technology Transfer

    Information in this technical report will be provided to the U.S. Army Engineer

    Distr ict a t Mobile, AL, for inclusion in t he new Corps of EngineersG uide S peci-

    fica tion for P refabr ica ted Oil-Wa ter Separ a tors for Militar y Applicat ions. I t wil l

    a lso be provided t o the D OD Clean Wa ter Act Services S teering Committ ee

    Oil/Wa ter S epar a tor Work G roup for fut ure upda te t o in t he Oil/Wa t er Sepa ra -

    tor Guidance Manual , which is currently under review prior to initial publica-

    tion.

    Units of Weight and Measure

    U .S. sta nda rd unit s of measure a re used in th is report . A ta ble of conversion fac-

    tors for S ta nda rd In terna tional (SI ) units is provided below.

    SI conversion factors

    1 gal = 3.78 L

    1 ft2

    = 0.093 m2

  • 8/13/2019 Ows Designing

    12/43

    12 ERDC/CERL TR-00-40

    2 Wash Water Characterization

    The information in this chapter summarizes the data obtained during studies

    conducted by C ERL during w hich sa mpling of oil/w a ter separ a tor influent wa s

    necessary. Hea dqua rt ers, U.S. Army Reserve Comma nd co-sponsored a CE RL

    study to characterize wash water at various Reserve maintenance faci l i t ies.

    Results from the unpublished report of that study (Gerdes 1997) are included

    below. Da ta from two studies sponsored by the U.S . Army E nvironmenta l Center

    a re a lso included, as w ell as da ta from a q uick-relea se detergent st udy conducted

    by CERL for the (former) U.S. Army Corps of Engineers Center for Public Works

    (1997).

    U.S. Army Reserve Study

    Onsite sampling efforts generated da ta chara cterizing w a stewa ter from severa l

    Army Reserve sources. CE RL sampling tea ms visited 11 w a stew a ter genera tors

    during th e stud y. An avera ge of eight sa mples were taken during a t ypica l wa sh-

    ing event at each generat or. Cha ra cteristics measur ed w ere: O&G , chemicaloxygen demand (COD), total suspended solids (TSS), volatile suspended solids

    (VSS ), a nd flow. Sa mples represent ed low -pressur e clea ning, high-pressur e

    cleaning, a nd cleaning w ith detergents. Sit es for these stud ies included:

    Tw o Avia t ion Su pport F a cilities (ASFs )

    Thr ee Area Ma int ena nce Su pport Activities (AMS As)

    Tw o Equ ipment Concentra tion Sit es (EC Ss)

    Three Reserve Center Orga nizat iona l Ma intena nce Shops (OMSs)

    Inf luent Characterizat ion: All Faci l i t ies

    Ta ble 1 summa rizes the wa sh wa ter an a lysis da ta from 10 sites visited. Flow a t

    the 10 wa shra cks summa rized in the ta ble ra nged from 1.5 gpm to 19 gpm. Av-

    erage flow at those washracks is about 7 gpm.

  • 8/13/2019 Ows Designing

    13/43

    ERDC/CERL TR-00-40 13

    Table 1. Summary of sampling data from 10 facilities.

    Parameter Average (mg/L) Peak (mg/L)

    O&G 316 1584

    TSS 1061 6502

    VSS 277 1584

    COD 2232 40,175

    G enerally, as flow increases, the concentra tion of conta mina nts decreases. Or,

    more a ccura tely, w hen high-pressure/low-flow w a shers a re used, conta mina nt

    concentr a tion tend s to be much higher t ha n w hen low-pressur e/high-flow hoses

    ar e used. Wa shrack wa stewa ter would never have the maximum conta minant

    concentr a tions (listed in Ta ble 1) th roughout a w a shing event. Flow a nd con-

    taminant levels vary significantly.

    Aviat ion Suppo rt Faci l i t ies

    CE RL personnel visited t w o of the t hree ASF s rema ining under th e command of

    th e Army Reserve. Ta ble 2 summa rizes the ana lysis dat a from sa mples obta ined

    during t hose visits.

    Table 2. Summary of ASF wash water characterization data.

    Parameter Average (mg/L) Peak (mg/L)

    O&G 594 1584

    TSS 625 1386

    VSS 408 1042

    COD 8478 40,175

    Helicopter wa shing is u sua lly done with modera te t o low -pressure wa shing (300

    psi or less) a t low flows (less th a n 5 gpm per hose). A va riety of surfa ce clea ning

    a gents a re used, all of which add considerable COD to th e wa stew a ter. At both

    locations, the surface cleaner was applied to the oily parts of the aircraft and al-

    lowed to soa k. Exceptionally high COD occurs in the wa sh wa ter wh en these

    par ts a re rinsed (see P eak COD ).

    About two-thirds of the suspended solids in the aircraft wash water are volatile.

    The sources of these volatile solids in the wash water are believed to be (1) the

    accumulation of vegetation particles that collect in the aircraft during takeoffs

    and landings, (2) the O&Gs that attach to the vegetation and inorganic soil par-

    ticles, and (3) traces of concentrated surface cleaner that remain attached to the

    soil part icles. The designer of pretreat ment for aircra ft w a shing should ta ke into

    considerat ion t he light d ensity solids. These solids will ha ve nea r neutr a l buoy-

    a ncy an d will pa ss over and un der baffles. It is recommended tha t some type of

  • 8/13/2019 Ows Designing

    14/43

    14 ERDC/CERL TR-00-40

    screening be used to remove these solids from th e wa ste strea m. Such a screen

    could help protect coa lescer sur fa ces in upst rea m oil/w a ter sepa ra tors fr om clog-

    ging. Screens would a lso benefit pretrea tment a t ground vehicle w a shra cks

    wh ere vehicle exteriors ar e wa shed.

    Area Maintenance Support A ctiv i t ies

    The AMSA shops perform a higher level of maint enan ce th a n t ha t performed in

    an OMS. It is simila r to tha t performed at D irect S upport ma intenance shops at

    lar ge U.S. Forces Comman d an d U.S . Army Tra ining and D octr ine Comma nd

    (FORS COM/TRADOC) inst a llat ions. With in the Reserves a re severa l hun dred

    AMSA shops. CE RL sam pling tea ms visited three of them. Ta ble 3 summa rizes

    the a na lysis da ta from sa mples obta ined during t hose visi ts .

    Table 3. Summary of AMSA wash water characterization data.

    Parameter Average (mg/L) Peak (mg/L)

    O&G 478 1419

    TSS 1272 6502

    VSS 416 1584

    COD 1841 10316

    Equipm ent Concentrat ion Sites

    Maintena nce shops at the E CSs ar e used to perform ma intenance similar t o that

    performed at AMSAs a nd OMSs. However, the avera ge chara cteristics of the

    wa sh wa ter were more simila r to tha t of OMS wa sh wa ter. This may be because

    one of th e EC S s visited used a low -pressur e/high-flow hose for w a shing, w hich

    tends to lower the concentr a tion of cont a mina nt s due to dilution. CE RL sam-

    pling team s visited two ECS s. Ta ble 4 summa rizes the an a lysis da ta from sa m-

    ples obta ined during th ose visits.

    Table 4. Summary of ECS wash water characterization data.

    Parameter Average (mg/L) Peak (mg/L)

    O&G 183 484

    TSS 1856 6015

    VSS 239 1359

    COD 692 3024

    Organizational Maintenance Shop s

    Maintenance performed at the organizational level is normally routine and does

    not require highly specia lized repair equipment. Wa shra cks a re used to clean

    vehicles returning from local (nontactical) usage and for cleaning vehicles before

  • 8/13/2019 Ows Designing

    15/43

    ERDC/CERL TR-00-40 15

    they are sent to an AMSA or Depot for more intensive repair or rebuilding.

    There are more than 1000 Army Reserve Centers (ARCs), most of which have an

    OMS. CE RL sa mpling tea ms visited th ree OMSs. Ta ble 5 summa rizes the

    analysis data from samples obtained during those visits.

    The vehicles washed at the OMSs visited were not very dirty, but this seems to

    be typica l of the soiling on vehicles wa shed at OMSs. Soaps a nd surfa ce cleaners

    a re seldom used a nd should not be used.

    Table 5. Summary of OMS wash water characterization data.

    Parameter Average (mg/L) Peak (mg/L)

    O&G 58 209

    TSS 611 3882

    VSS 77 182

    COD 99 262

    Other Sites

    For t L ee, VA Transpor tat i on M otorpool . Wash wa ter from the tra nsporta t ion

    motorpool (TMP) washrack was sampled during an evaluation of a simple grav-

    ity sepa ra tor retr ofitted w ith coa lescing tubes (G erdes 1998). The results of the

    analysis of the separator influent samples are as follow:

    TSS -- 210 mg/L O&G -- 241 mg/L

    Army N ati onal Guar d Or ganizati onal M ain tenance Shops. Wa sh w a ter from

    tw o OMS wa shra cks were an alyzed during a study sponsored by the Army E nvi-

    ronmenta l Center (AEC ) (Hu dson and G erdes 1998). The results of wa sh w a ter

    an alysis a re a s follow:

    Tota l P et roleu m H yd roca rb ons (TP H ) -- 406 mg/L pea k -- 1380 mg /L

    Fort L ewi s M ain tenance Support B atal l i on. Wa sh wa ter from a vehicle ma in-

    tenance wa sh a rea inside a Fort Lewis motorpool wa s a na lyzed during a study toevalua te a quick-relea se detergent (U SACE P WTB ). The results of the w a sh w a -

    ter a nalysis ar e as follow:

    O&G -- 250 mg/L TSS -- 700 mg/L

  • 8/13/2019 Ows Designing

    16/43

    16 ERDC/CERL TR-00-40

    Summary

    All of t he va lues report ed in t his chapt er (except peak va lues) a re a verages of the

    a na lyses of several sa mples t a ken over the course of one or more vehicle wa shing

    events. It is obvious tha t Army w a sh wa ter conta ins a wide ran ge in the concen-

    tr a tions of O&G a nd TSS . The avera ge concentra tion of O&G a t t he different

    ty pes of w a shr a cks ra nged fr om 58 mg/L to 594 mg/L. The peak concent ra tions

    mea sur ed ra ng ed from 209 mg/L to 1584 mg/L. Avera ge TSS concent ra tions

    ra nged fr om 210 mg/L to 1272 mg/L. P ea k TSS concentr a tions r a nged fr om 1386

    mg/L t o 6502 mg/L.

  • 8/13/2019 Ows Designing

    17/43

    ERDC/CERL TR-00-40 17

    3 Treatability Study

    Experiment Design

    The overall purpose of the experiment was to determine how well various con-

    figurations of coalescers could treat fabricated Army wash water, and more spe-

    cifically, to determine if buildup of solids within the coalescer structure would

    negat ively affect performa nce. Such a st udy ha s numerous par a meters (i .e., con-

    centration of O&G, concentration of TSS, coalescer material, incline angle of coa-lescer sur fa ces, coalescer surfa ce spacing, surfa ce loa ding ra te of th e wa sh w a ter,

    wa ter temperat ure, and dura tion of the test runs). The resources a va ilable to

    the project limited th e number of experiment a l configura tions. Configurat ions

    were selected that would most efficiently achieve the goals of the project.

    To conduct t he experiment , pilot-sca le P lexigla s test cells were constr ucted. Tw o

    sets of test cells were used, each with four parallel cells fed by one source of

    w a stew a ter. A uniq ue coa lescer configura tion wa s pla ced in each cell. The cells

    were constructed with overflow influent weirs set to equalize flow to all four

    cells. U nderflow effluent ba ffles were used to cont a in the separ a ted O&G .

    Wa stewa ter w a s mixed in tw o 55-ga l drums, each of which fed wa stew a ter by

    gra vity t o one of th e sets of four t est cells. Figure 2 show s th e test cells.

    Figure 2. Eight test cells operating in parallel.

  • 8/13/2019 Ows Designing

    18/43

    18 ERDC/CERL TR-00-40

    Contaminants

    The concentrations of O&G and TSS were not variable parameters during the

    study, a nd were kept as consta nt a s possible. Inst ead, conta mina nt levels w ere

    used tha t r epresented the upper ran ge of the levels measured during t he cha ra c-

    ter iza tion stu dy. The concentr a tion of oil in th e test cell influent w a s kept close

    to th e ra nge of 450 to 500 mg/L. No at tempt w a s ma de to keep th e concentr a tion

    of oil in t he test cell influent consta nt, a s a va ria ble concent ra tion wa s more rep-

    resenta tive of Army wa shra ck wa stew a ter. U sed oil from Army ma intena nce

    shops, primar ily a mixture of motor oil an d hyd ra ulic oil , wa s used wh en mixing

    the fabrica ted wa stewa ter.

    The concent ra tion of TSS w a s kept close to a r a ng e of 150 to 250 mg/L. Tha t con-

    centration is lower than what was measured during the characterization study.More tha n ha lf of the sol ids in wa sh wa ter a re larger pa rticles tha t t end to sett le

    out in a gri t basin or a t t he head end of a separ at or, a nd do not pa ss through the

    coa lescer. Only fine silt and clay par ticles were mixed in the fabr ica ted

    wa stewa ter influent. Sediment from the effluent end of a centra l ized wa sh

    facility sedimenta tion basin w a s used as th e source.

    Clean tap water, oil , and a sediment slurry were fed into a mixing barrel to cre-

    a te th e wa stew a ter for the test cell experiments. As the components w ere fed

    into the bar rel, they w ere consta nt ly mixed with a motorized propeller. The

    wastewater overflowed by gravity into a trough, from which the wastewater

    passed over w eirs into the individua l test cells. Ta p wa ter flow into the mixing

    drum w a s consta ntly measured with a flow meter. Flow from each test cel l wa s

    periodically measur ed man ua lly. The oil and sediment w ere fed using pa ra sta llic

    metering pumps.

    Coalescer Material

    Two ma teria ls w ere used for t he par a llel plat e coa lescers polypropylene and

    high densit y polyeth ylene. P olypropylene is th e more oleophilic of th e tw o plas-tics, a nd seems t o be th e most commonly u sed ma ter ia l in off-th e-shelf oil/w a ter

    separ a tors. Some people in the indust ry believe th a t polypropylene is too oleo-

    philic a nd does not a llow oil to migrat e to th e wa ter surfa ce. P olyethylene, a n-

    other commonly used material, was chosen as an alternative material for com-

    parison.

  • 8/13/2019 Ows Designing

    19/43

    ERDC/CERL TR-00-40 19

    Coalescing Plate Angle of Incl ine

    Separ a tor ma nufa cturers commonly use two a ngles of incline to the horizont a l

    45 a nd 60 degrees. These tw o angles w ere used for most of th e test cell configu-

    ra tions. The 45-degree a ngle w a s used in tw o configur a tions one with the

    plates at a 45-degree angle to the horizontal inlet-to-outlet axis; and the other

    with the plates parallel to the horizontal inlet-to-outlet axis (looking like an in-

    verted V). Dur ing the first t est period, one test cell had vertical plat es pa ra llel to

    th e horizonta l flow. Dur ing the second test period, tw o cells purchased for test-

    ing were configured with a waffle-shaped polyethylene coalescer, a proprietary

    design of La nda Wa ter Cleaning Sy stems (Ca ma s, WA).

    Water Temperature

    Due to resource restraints , wa ter temperatur e was not used as a va riable. Be-

    cause of the design of the wa stewa ter mixing a ppar at us, the tempera ture of the

    test cell influent w a s consistent for a ll cells. The temperat ure in th e test cells

    wa s close to tha t of th e cold ta p wa ter source, a nd w a s assum ed to be represent a -

    tive of the w a ter tempera ture a t most outdoor Army w ashr acks.

    Conf igurat ions

    Figure 3 show s th e six basic configura tions used during this st udy. The pla te

    positioning a nd flow direction of the individual test cells were a s follows:

    Polypropylene 45oDownwa rd f low

    Polyethylene 45oDownwa rd f low

    Polypropylene 60oDownwa rd f low

    Polyethylene 60oDownwa rd f low

    Polypropylene 45

    o

    Horizonta l flow

    Polyethylene 45oHorizont a l flow

    Polypropylene 90oHorizonta l flow

    Polyethylene 90oHorizont a l flow

    Landa wa ffle a ngled ribs slanted t owa rd t he horizonta l flow

    Landa wa ffle a ngled ribs slanted a wa y from the horizonta l flow

  • 8/13/2019 Ows Designing

    20/43

    20 ERDC/CERL TR-00-40

    Top View

    (plates perpendicular to page)

    Flow

    (corrugated plates

    parallel to page)

    Flow

    (corrugated plates

    parallel to page)

    Flow

    (plates perpendicular to page)

    Flow

    45

    (plates perpendicular to page)

    Flow

    60

    (flow and plates

    perpendicular to page)

    45

    Figure 3. Coalescer configurations.

    Duration

    The fabricated wash water was allowed to run through the test cells for periods

    of 2 hr. Resear chers ra n one 2-hr test per da y. This schedule wa s to a pproxi-

    ma te a t ypical 1-day use at a n Army w ashr ack. Ini t ial ly ea ch test cel l wa s oper-

    ated for at total of at least 100 hr, to represent approximately 1 year s usage a t

    an average Army w a shrack.

    The polypropylene coa lescer t est cells w ere opera ted for a n extend ed period. The

    intent was to determine if performance would eventually drop significantly due

    to an excessive buildup of oil a nd solids on th e coa lescer surfa ces. E ssent ia lly

    th e extended test w a s to determine if the coa lescer w a s a ctua lly performing more

    as a f il ter a nd thus breakthrough could occur.

    Surface Loading Rate

    The surface loading rate for the initial test period was set according to the sur-

    face loading ra te equa tion in AP I s oil/w a ter sepa ra tor design m a nua l (AP I 1992,p 26) for removing 60-micron oil particles.

    Surfa ce loa ding rate = Qm/A

    H= 0.00386(S

    w- S

    o)/

    Qm= design flow (ft

    3/min )

    AH= projected horizonta l ar ea (ft

    2) for a ll coa lescing su rfa ces (one side for

    each pla te)

  • 8/13/2019 Ows Designing

    21/43

    ERDC/CERL TR-00-40 21

    Sw= specific gra vity of w a ter

    So= specific gra vity of oil

    = wa stewa ter viscosi ty in poise

    Design flow w a s set a t 1.5 gpm (0.20 cfm) for ea ch test cell. The projected h ori-

    zonta l ar ea for th e coa lescer ma teria l in each test cell wa s a pproximat ely 4.08 ft2.

    The sur fa ce loa ding r a te for th e first t est period wa s 0.37 gpm/ft2 (0.05 cfm/ft

    2).

    Su rfa ce loadin g r a tes of 0.25 gpm/ft2a nd 0.49 gpm/ft

    2were used for a few of the

    configura tions in a la ter t est period.

    Sampling and Analysis

    Influent and effluent composite samples were taken after every fifth 2-hr test

    cell opera tion run (i.e., a fter 10 hr of opera tion). Sa mples w ere ta ken more fre-

    quently at the beginning of each test cell experiment to adjust the contaminant

    feed pumps and establish the desired contaminant levels in the fabricated wash

    w a ter. TSS a na lysis w a s done a ccording to St a nda rd Methods. Ana lysis for

    O&G was done according to a variation of EPA Method 1664, Revision A, devel-

    oped by 3M Company and sanctioned by the U.S. Environmental Protection

    Agency (U SE PA). An independent study ha s shown t ha t this test ha s equiva lent

    or great er a ccura cy tha n t he original Method 1664.

    Test Start-up

    At t he beginning of each experiment, th e coalescer ma teria l in each t est cell wa s

    coa ted wit h oil . The int ent wa s to season th e surfa ces in order to eliminat e the

    initial period of oil accumula tion, a nd thu s a llow oil remova l in th e test cells to

    a chieve a st eady sta te more quickly.

    Results

    Graphs showing all results of the test cell sampling analysis are shown in the

    a ppendix. The following pa ra gra phs describe CE RL s interpretat ion of tha t da ta .

    Oil and Grease Removal

    During the first 100 hr of operation, the down-flow, 45 degree, polypropylene

    platesprovided the best effluent qu a lity a t t he overflow r a te of 0.37 gpm/ft2.

    H owever, the oil concentr a tion in t he test cell influent w a s over 50 mg/L less

  • 8/13/2019 Ows Designing

    22/43

    22 ERDC/CERL TR-00-40

    th a n for th e polyeth ylene test cells. Du ring th e second 100 hr of opera tion, the

    concentration of oil in the influent to the polypropylene plate cells was closer to

    the level going to the polyethylene plate test cells, and performance dropped be-

    low th a t of t he dow n-flow, 60-degree, polyet hylene.

    Only the 60-degree down-flow configuration of the polyethylene plates provided

    consistent treatment performance in achieving the target effluent level of 100

    mg/L oil at t he su rf a ce loa din g r a te of 0.37 gpm/ft2. However, a t a surface loa d-

    ing ra t e of 0.25 gpm/ft2, both the 45- and 60-degree, down-flow, polypropylene

    configura tions provided consistent, a cceptable tr eat ment.

    P olyethylene appear ed to be the better of the tw o coa lescer ma teria ls. There ar e

    other ma teria ls tha t could not be tested, however, due to limited resources, a nd it

    is possible tha t some of those perform a s w ell or better t ha n polyethy lene.

    Sediment Accum ulat ion

    There was no visual evidence that sediment accumulation on the surface of the

    coa lescer pla tes w ould ha ve ca used interference with the performa nce of th e test

    cells. Sediment coa ted th e top surfa ce of each of the coa lescer plat es, but ap-

    peared to migrate to the bottom of the separation chamber before reaching a

    th ickness of 0.1 in. The concentr a tion of TSS in th e effluent r ema ined fa irly con-

    sta nt for a ll configura tions, and seemed to decrease slightly over t ime for a few of

    the configura tions during t he test period.

  • 8/13/2019 Ows Designing

    23/43

    ERDC/CERL TR-00-40 23

    4 Conclusions and Recommendations

    Conclusions

    1. The test cell configur a tion wit h polyeth ylene pla tes insta lled a t a 60-degree

    an gle an d ha ving a downw ar d flow seemed to provide the best t reatment at

    th e loa din g ra t e of 0.37 gpm/ft2.

    2. There wa s no evidence th a t, dur ing th e norma l opera tion of an oil/w a tersepa ra tor, a lay er of sediment w ould collect on coa lescer pla tes a t a th ickness

    that would interfere with flow through the coalescer, assuming the plate

    spacing wa s a t least 0.75 in.

    Recommendations

    1. When s pecifying off-th e-shelf, coa lescing, oil/w a ter separ a tors, recommend

    the following:

    Coalescer plate material: Polyethylene

    Ma ximum surf a ce loa ding ra te: 0.37 gpm/ft2

    Coa lescer plat e a ngle: 60 degrees

    Direction of flow: Downw a rd a t 60 degrees to the horizonta l

    2. Coalescing sepa ra tor designs must provide stora ge for solids removed withinthe coalescer.

  • 8/13/2019 Ows Designing

    24/43

    24 ERDC/CERL TR-00-40

    References

    American P etroleum I nstit ute (AP I), Monographs on Refinery E nvi ronm ental Control - M anage-

    ment of Water Di schar ges; Design and Operati on of Oil / Water Separators, AP I P ublica tion 421,

    Firs t E d., Februa ry 1990 (revised November 1992).

    Brincks, Richard, Oil/Wa ter Sepa ra tors-Design & Selection, Envi ronm ental Techn ology,

    Ma y/J un e 1996, pp 44-46.

    G erdes, G a ry, Trip Report for Fort Lee, VA, 31 Ma rch 1998.

    Gerdes, Ga ry L. , Cha ra cterization of Oil/Wa ter Separa tor Influent at U.S . Army Reserve Fa cili-

    ties , U.S. Army C onstruction Engineering Resear ch Labora tory (USACERL) Letter Report

    (unpublis hed), November 1997.

    Hudson, Kenneth L. a nd G ary L. Gerdes, A D ecision Tree for I mpr ovin g Washrack Oil / Water Sepa-

    rator Operat i ons, U SAEC Report No. SF IM-AEC -ET-R-98003, J a nua ry 1998.

    U. S. Army Center for Public Works, Oil/Wat er Separa tor Selection, Inst alla tion, a nd Ma inte-

    na nce: Lessons Learned, Techni cal B ullet in N o. 200-1-05, 5 December 1997.

    U.S . Army Corps of Engineers (USACE), Selection an d Design of Oil/Wa ter Sepa ra tors a t Arm yFacilities, Techni cal Let ter No. 1110-3-466, 26 Augu st 1994.

    USACE, Effect of Quick Release Detergen t on Oil/Wa ter S epara tors, P ublic Works Technical B ul-

    letin 420-49-28 (pendin g).

  • 8/13/2019 Ows Designing

    25/43

    ERDC/CERL TR-00-40 25

    Appendix: Results of Test Cell Sampling

    Polypropylene-45 degrees- Downward Flow: Total Suspended Solids vs Time ( overflow rate: 0.37 gpm/sq ft )

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120 140 160 180 200

    time (hrs)

    TSS(ppm)

    Influent Effluent

    Figure A1. Polypropylene 45 degrees downward flow: TSS at surface loading rate of 0.37

    gpm/ft2.

  • 8/13/2019 Ows Designing

    26/43

    26 ERDC/CERL TR-00-40

    Polypropylene-45 degrees- Downward Flow: Grease and Oil vs Time (ove rflow rate: 0.37 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120 140 160 180 200

    time (hrs)

    G&O

    (ppm)

    Influent Effluent

    Figure A2. Polypropylene 45 degrees downward flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Polypropylene-60 degrees- Downward Flow: Total Suspended Solids vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120 140 160 180 200

    time (hrs)

    TSS(ppm)

    I nfluent E ffluent

    Figure A3. Polypropylene 60 degrees downward flow: TSS at surface loading rate of 0.37

    gpm/ft2.

  • 8/13/2019 Ows Designing

    27/43

    ERDC/CERL TR-00-40 27

    Polypropylene-60 degrees- Downward Flow: Grease and Oil vs Time (overflow rate: 0.37 gpm/sq f t)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120 140 160 180 200

    time (hrs)

    G&O

    (ppm)

    Influent Effluent

    Figure A4. Polypropylene 60 degrees downward flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Polypropylene-90 degrees- Horizontal Flow: Total Suspended Solids vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    Influent Effluent

    Figure A5. Polypropylene 90 degrees horizontal flow: TSS at surface loading rate of 0.37

    gpm/ft2.

  • 8/13/2019 Ows Designing

    28/43

    28 ERDC/CERL TR-00-40

    Polypropylene-90 degrees- Horizontal Flow: Grease and Oil vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120

    time (hrs)

    G&O

    (ppm)

    Influent Effluent

    Figure A6. Polypropylene 90 degrees horizontal flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Polypropylene-45 degrees- Horizontal Flow: Total Suspended Solids vs Time (overflow rate: 0.37 gpm/sq f t)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    Inf luent Ef fluen t

    Figure A7. Polypropylene 45 degrees horizontal flow: TSS at surface loading rate of 0.37

    gpm/ft2.

  • 8/13/2019 Ows Designing

    29/43

    ERDC/CERL TR-00-40 29

    Polypropylene-45 degrees- Horizontal Flow: Grease and Oil vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120

    time (hrs)

    G&O

    (ppm)

    Influent Effluent

    Figure A8. Polypropylene 45 degrees horizontal flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Polyethylene-45 degrees- Downward Flow: Total Suspended Solids vs T ime (overflow rate: 0.37 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    Influent Effluent

    Figure A9. Polyethylene 45 degrees downward flow: TSS at surface loading rate of 0.37 gpm/ft2.

  • 8/13/2019 Ows Designing

    30/43

    30 ERDC/CERL TR-00-40

    Polyethylene-45 degrees- Downward Flow: Grease and Oil vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120

    time (hrs)

    G&O

    (ppm)

    Influent Effluent

    Figure A10. Polyethylene 45 degrees downward flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Polyethylene-60 degrees- Downward Flow: Total Suspended Solids vs Time (overflow rate: 0.37 gpm/sq ft )

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    I nfluent Effluent

    Figure A11. Polyethylene 60 degrees downward flow: TSS at surface loading rate of 0.37

    gpm/ft2.

  • 8/13/2019 Ows Designing

    31/43

    ERDC/CERL TR-00-40 31

    Polyethylene-60 degrees- Downward Flow: Grease and Oil vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    Influent Effluent

    Figure A12. Polyethylene 60 degrees downward flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Polyethylene-90 degrees- Horizontal Flow: Total Suspended Solids vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    Influent Ef fluent

    Figure A13. Polyethylene 90 degrees horizontal flow: TSS at surface loading rate of 0.37

    gpm/ft2.

  • 8/13/2019 Ows Designing

    32/43

    32 ERDC/CERL TR-00-40

    Polyethylene-90 degrees- Horizontal Flow: Grease and Oil vs Time (overfl ow rate: 0.37 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    I nfluent Effluent

    Figure A14. Polyethylene 90 degrees horizontal flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Polyethylene-45 degrees- Horizontal Flow: Total Suspended Solids vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    Influent Effluent

    Figure A15. Polyethylene 45 degrees horizontal flow: TSS at surface loading rate of 0.37

    gpm/ft2.

  • 8/13/2019 Ows Designing

    33/43

    ERDC/CERL TR-00-40 33

    Polyethylene-45 degrees- Horizontal Flow: Grease and Oil vs Time (overfl ow rate: 0.37 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    In fluent Effluent

    Figure A16. Polyethylene 45 degrees horizontal flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Corrugated-angled ribs slanted away from f low: Total Suspended Solid vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    Influent Effluent

    Figure A17. Corrugated angled ribs slanted away from flow: TSS at surface loading rate of 0.37

    gpm/ft2.

  • 8/13/2019 Ows Designing

    34/43

    34 ERDC/CERL TR-00-40

    Corrugated-angled ribs slanted away from flow: Grease and Oil vs Time (overflow rate: 0.37 gpm/sq ft )

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120

    time (hrs)

    G&O

    (ppm)

    Influent Effluent

    Figure A18. Corrugated angled ribs slanted away from flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Corrugated-angled ribs slanted toward flow: Total Suspended Solids vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 20 40 60 80 100 120

    time (hrs)

    TSS(ppm)

    Influent E ffluent

    Figure A19. Corrugated angled ribs slanted toward flow: TSS at surface loading rate of 0.37

    gpm/ft2.

  • 8/13/2019 Ows Designing

    35/43

    ERDC/CERL TR-00-40 35

    Corrugated-angled ribs slanted toward flow: Grease and Oil vs Time (overflow rate: 0.37 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 20 40 60 80 100 120

    time (hrs)

    G&O

    (ppm)

    Influent Effluent

    Figure A20. Corrugated angled ribs slanted toward flow: O&G at surface loading rate of 0.37

    gpm/ft2.

    Corrugated-angled ribs slanted away from f low: Total Suspended Solids vs Time (overflow rate: 0.25 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 10 20 30 40 50 60 70

    time (hrs)

    TSS(ppm)

    Influent Effluent

    Figure A21. Corrugated angled ribs slanted away from flow: TSS at surface loading rate of 0.25

    gpm/ft2.

  • 8/13/2019 Ows Designing

    36/43

    36 ERDC/CERL TR-00-40

    Corrugated-angled ribs slanted away from flow: Grease and Oil vs Time (overflow rate: 0.25 gpm/sq ft )

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 10 20 30 40 50 60 70

    time (hrs)

    G&O

    (ppm)

    I nf luent Effluent

    Figure A22. Corrugated angled ribs slanted away from flow: O&G at surface loading rate of 0.25

    gpm/ft2.

    Corrugated-angled ribs slanted toward flow: Total Suspended Solids vs Time (overflow rate: 0.25 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 10 20 30 40 50 60 70

    time (hrs)

    TSS(ppm)

    I nf luent E ffluent

    Figure A23. Corrugated angled ribs slanted toward flow: TSS at surface loading rate of 0.25

    gpm/ft2.

  • 8/13/2019 Ows Designing

    37/43

    ERDC/CERL TR-00-40 37

    Corrugated-angled ribs slanted toward flow: Grease and Oil vs Time (overflow rate: 0.25 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 10 20 30 40 50 60 70

    time (hrs)

    G&O

    (ppm)

    Influent Effluent

    Figure A24. Corrugated angled ribs slanted toward flow: O&G at surface loading rate of 0.25

    gpm/ft2.

    Corrugated-angled ribs slanted away from flow: Total Suspended Solids vs Time (overflow rate: 0.49 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 5 10 15 20 25 30 35 40

    time (hrs)

    TSS(ppm)

    In fluent E ffluen t

    Figure A25. Corrugated angled ribs slanted away from flow: TSS at surface loading rate of 0.49

    gpm/ft2.

  • 8/13/2019 Ows Designing

    38/43

    38 ERDC/CERL TR-00-40

    Corrugated-angled ribs slanted away from flow: Grease and Oil vs Time (overflow rate: 0.49 gpm/sq ft )

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 5 10 15 20 25 30 35 40

    time (hrs)

    G&O(ppm)

    Influent Effluent

    Figure A26. Corrugated angled ribs slanted away from flow: O&G at surface loading rate of 0.49

    gpm/ft2.

    Corrugated-angled ribs slanted toward flow: Total Suspended Solids vs Time (overflow rate: 0.49 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 5 10 15 20 25 30 35 40

    time (hrs)

    TSS(ppm)

    Influent Effluent

    Figure A27. Corrugated angled ribs slanted toward flow: TSS at surface loading rate of 0.49

    gpm/ft2.

  • 8/13/2019 Ows Designing

    39/43

    ERDC/CERL TR-00-40 39

    Corrugated-angled ribs slanted toward flow: Grease and Oil vs Time (overflow rate: 0.49 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 5 10 15 20 25 30 35 40

    time (hrs)

    G&O

    (ppm)

    Influent Effluent

    Figure A28. Corrugated angled ribs slanted toward flow: O&G at surface loading rate of 0.49

    gpm/ft2.

    Polypropylene-45 degrees- Downward Flow: Total Suspended Solids vs Time (overflow rate: 0.25 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 5 10 15 20 25 30 35 40

    time (hrs)

    TSS(ppm)

    Influent Effluent

    Figure A29. Polypropylene 45 degrees downward flow: TSS at surface loading rate of 0.25

    gpm/ft2.

  • 8/13/2019 Ows Designing

    40/43

    40 ERDC/CERL TR-00-40

    Polypropylene-45 degrees- Downward Flow: Grease and Oil vs Time (overflow rate: 0.25 gpm/sq ft)

    0

    100

    200

    300

    400

    500

    600

    700

    800

    0 5 10 15 20 25 30 35 40

    time (hrs)

    G&O

    (ppm)

    Influent Ef fluent

    Figure A30. Polypropylene 45 degrees downward flow: O&G at surface loading rate of 0.25

    gpm/ft2.

    Polypropylene-60 degrees- Downward Flow: Total Suspended Solids vs Time (overflow rate: 0.25 gpm/sq ft)

    0

    50

    100

    150

    200

    250

    300

    350

    400

    450

    500

    0 5 10 15 20 25 30 35 40

    time (hrs)

    TSS(ppm)

    Inf luent Ef fluent"

    Figure A31. Polypropylene 60 degrees downward flow: TSS at surface loading rate of 0.25

    gpm/ft2.

  • 8/13/2019 Ows Designing

    41/43

  • 8/13/2019 Ows Designing

    42/43

    42 ERDC/CERL TR-00-40

    CERL Distribution

    Chief of EngineersATTN: CEHEC-IM-LH (2)

    ATTN: HECSA Mailroom (2)ATTN: CECC-RATTN: CECW-EW

    Engineer Research and Development Center (Libraries)ATTN: ERDC, Vicksburg, MSATTN: Cold Regions Research, Hanover, NHATTN: Topographic Engineering Center, Alexandria, VA

    Defense Tech Info Center 22304ATTN: DTIC-O

    106/00

  • 8/13/2019 Ows Designing

    43/43

    REPORT DOCUMENTATION PAGEForm Approved

    OMB No. 0704-0188Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintainingdata needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reduthis burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22204302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of i nformation if it does not display a curvalid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.

    1. REPORT DATE (DD-MM-YYYY)

    12-20002. REPORT TYPE

    Final3. DATES COVERED (From - To)

    5a. CONTRACT NUMBER

    5b. GRANT NUMBER

    4. TITLE AND SUBTITLE

    Designing Coalescing Oil/Water Separators for Use at Army Washracks

    5c. PROGRAM ELEMENT NUMBER

    5d. PROJECT NUMBER

    62720A896

    5e. TASK NUMBER

    6. AUTHOR(S)

    Gary L. Gerdes, Angelo DeGuzman, and Jeffrey Grubich

    5f. WORK UNIT NUMBER

    TB0

    8. PERFORMING ORGANIZATION REPORNUMBER

    7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

    U.S. Army Engineer Research and Development Center (ERDC)

    Construction Engineering Research Laboratory (CERL)

    P.O. Box 9005

    Champaign, IL 61826-9005

    ERDC/CERL TR-00-40

    9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITORS ACRONYM(S)

    CECW-EWU.S. Army Corps of Engineers

    20 Massachusetts Avenue, NW.

    Washington, DC 20314-1000 11. SPONSOR/MONITORS REPORTNUMBER(S)

    12. DISTRIBUTION / AVAILABILITY STATEMENT

    Approved for public release; distribution is unlimited.

    13. SUPPLEMENTARY NOTESCopies are available from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161.

    14. ABSTRACT

    The U.S. Army has thousands of oil/water separators to treat wastewater from tactical vehicle washracks at active Army, Army Re-

    serve, and Army National Guard facilities. The Army continues to purchase and install new separators when existing separators mus

    be replaced, and when new vehicle maintenance facilities are being constructed. Most off-the-shelf separators being installed curren

    are coalescing-type gravity separators.

    No Army guidance exists, however, to help environmental and Directorate of Public Works personnel purchase coalescing separator

    that are applicable to the high solids wash water at a typical Army washrack. Because Army guidance did not exist, and vendor guid

    ance is not applicable, this study was conducted so that installation personnel, as well as washrack designers, have specific guidance

    for the selection of off-the-shelf coalescing oil/water separators.

    This research concluded in the following specifications for off-the-shelf, coalescing, oil/water separators: coalescer plate material polyethylene; maximum surface loading rate 0.37 gpm/ft2; coalescer plate angle 60 degrees; direction of flow downward at 60

    degrees to the horizontal.

    15. SUBJECT TERMS

    oil/water separators, washrack, vehicle maintenance, tactical equipment maintenance, coalescers, waste water

    16 SECURITY CLASSIFICATION OF: 17 LIMITATION 18 NUMBER 19a NAME OF RESPONSIBLE PERS