Dave  Mercer,  P.E.  District  Engineer  DEQ  

Disinfec(on  Byproducts  (DBPs):  TTHMs  and  HAA5s  •  DBPs  =  compounds  created  when  naturally  occurring  material  in  water  react  with  the  disinfectant  used  to  treat  the  water  

•  TTHMs  =  Total  Trihalomethanes:    a  group  of  DBPs  regulated  under  the  Stage  2  DBPR  

•  HAA5  =  Haloacetic  acids:    a  group  of  DBPs  regulated  under  the  Stage  2  DBPR  

Precursor  in  Water  Natural  Organic  MaAer  

Bromide   +Added  Disinfectant  

Chlorine  

Chloramines  

Chlorine  Dioxide  

Ozone  

How  Are  DBPs  Formed?  

= TTHM  (Total  Trihalomethanes)  HAA5  (Haloace(c  Acids)  

Chlorite  

Bromate  

DBP  

How  Are  DBPs  Formed?  Natural  Organic  

MaAer   +Added  

Disinfectant   = DBP  Natural  Organic  

MaAer   +Added  

Disinfectant   = DBP  Natural  Organic  MaAer   +

Added  Disinfectant   = DBP  + Time    

Disinfec(on  Byproducts  TTHM    ! MCL  =  0.080  mg/l                    (80  ppb)  ! Chloroform  ! Dibromochloroform  ! Dichlorobromoform  ! Bromoform    

HAA5    ! MCL  =  0.060  mg/l                    (60  ppb)  ! Monochloroacetic  acid  ! Dichloroacetic  acid  ! Trichloroacetic  acid  ! Monobromoacetic  acid  ! Dibromoacetic  acid  

TOC  ! Based  on  past  12  months  of  raw  and  finished  water  TOC  data  

! Determine  performance  ratio  (%  TOC  actual  removal  versus  required)  

TOC  Month TOC Raw Alkalinity Raw

TOC Finished

Req'd % Removal

Actual % Removal SUVA Ratio

Removal Ratio

04/13 3.6 17.35 1.1 35 68.55 — 1.96

05/13 3.3 19 1.3 35 61.7 — 1.76

06/13 4.2 16.9 1.8 45 57.2 — 1.27

07/13 5.3 14.9 2.4 45 55.9 — 1.24

08/13 5.7 18.1 2 45 64.3 — 1.43

09/13 5.2 20.1 2.9 45 44.8 — 1

10/13 4.9 15.3 2.5 45 48.9 — 1.09

11/13 4.7 16.8 2.8 45 40.6 — 0.9

12/13 5 18.2 2.7 45 45.5 — 1.01

01/14 5.2 14.6 2.7 45 47 — 1.04

02/14 4.9 14.2 2.1 45 57.6 — 1.28

03/14 3.3 15.5 1.6 35 51.2 — 1.46

Averages: 4.6   2.15     — 1.29

TOC  Monitoring  Points  

Raw  Water   Clarifiers   Filters   Clearwell  

Chemical Addition

Raw TOC Finished TOC

Prior to chemical addition No later than the CFE

Reducing  Total  Organic  Carbon    

Natural  Organic  MaAer  

(measured  as  TOC)  

+Added  

Disinfectant   = DBP  

TOC  –  Coagula(on  ! The   removal   of   natural   organic  matter,  measured   as  TOC,   in   a   conventional   water   treatment   by   the  addition   of   coagulant   has   been   demonstrated   by  laboratory   research  and  by  pilot,  demonstration,  and  full  scale  studies.  

TOC  Removal  ! TOC  plays  a  key  role  in  DBP  formation  –  even  a  small  increase  in  TOC  can  lead  to  an  increase  in  DBP  formation!  

! Removal  of  TOC  occurs  in  most  plants,  but  it  may  not  be  optimized!  

Enhanced  Coagula(on  Enhanced  coagulation  can  include  one  or  more  of  the  following  operational  changes:  !  Increasing  coagulant  dose  !  Changing  coagulant  !  Adjusting  pH  (using  acid  to  lower  the  pH  as  low  as  5.5)  !  Improving  mixing  or  applying  moderate  dosage  of  an  oxidant  or  PAC  

!  Adding  a  polymer  !  TOC  should  be  2.0  mg/L  or  less  at  the  clarifier  effluent  

Jar  Tes(ng  !  Jar   testing   is   a   method   of   simulating   a   full-‐scale  water  treatment  process,  providing  system  operators  a  reasonable   idea  of   the  way  a   treatment  chemical  will  behave   and   operate   with   a   particular   type   of   raw  water.  

! Nowadays,  jar  testing  must  include  TOC  analyses.  

Jar  Tes(ng  !  It  is  important  to  simulate  physical  conditions  such  as  mixing,  detention  times,  and  solids  recycle  in  the  jar  test  corresponding  to  those  conditions  in  the  full-‐scale  water  treatment  plant.  

Jar  Tes(ng  The  jar  testing  process  can  be  summarized  as  follows:  !  For  each  water  sample  (usually  raw  water)  a  number  of  beakers  (jars)  are  filled  with  equal  amounts  of  the  water  sample;  

!  Each  beaker  of  the  water  sample  is  treated  with  a  different  dose  of  the  chemical;  

!  Other   parameters   may   be   altered   besides   dosage,   including  chemical  types,  mixing  rate,  pH,  etc.;  

!  By   comparing   the  final  water   quality   achieved   in   each  beaker,  the   effect   of   the   different   treatment   parameters   can   be  determined;    

!  Jar  testing  is  normally  carried  out  on  several  beakers  at  a  time,  with   the   results   from   the   first   test   guiding   the   choice   of  parameter  amounts  in  the  later  tests.  

When  should  jar  tests  be  performed?  

Seasonally Daily, Weekly, Monthly

Change in chemical

Change in raw water

quality

New pumps

Change in flow

New mixer motor

pH adjustment

Cost  Savings    

Jar  Test  Equipment   Overfeeding   Underfeeding  

$3,000   • Chemical  Price  • Delivery  • Backwash  Water    • Residuals  Disposal  

• Disinfectant  Price  • Violations  (public  notice)  • Consent  Order  (penalties)  

Solids  Contact  Clarifier  –  Design  !  30  seconds  rapid  mix  (no  greater  than)  !  30  minutes  flocculation  (no  less  than)  !  3  hours  sedimentation  (no  less  than)  

Rapid Mix

Flocculation Flocculation

Sedimentation Sedimentation

Solids  Contact  Clarifier  -‐  Design  ! Need  dimensions  of  each  zone  (where  are  those  old  plans?)  

! Need  flow  through  clarifier  (gpm)     50 ft

12 ft

12 ft

8 ft

16 ft

2 ft

Example

Solids  Contact  Clarifier  -‐  Design  ! Determine  rapid  mix  zone  volume  (gal)  

!  Volume  of  cylinder    ! Determine  flocculation  zone  volume  (gal)  

!  Volume  of  frustum  (V=  π  ·∙                      ·∙  (R2  +  Rr  +  r2))  ! Determine  sedimentation  zone  volume  (gal)  

!  Total  volume  minus  flocculation  zone  volume    

h  

3  

Ques(ons  aIer  reviewing  design:  !  Is  the  rapid  mix  rapid?  !  Is  the  clarifier  operating  as  designed  (anything  need  to  be  repaired)?  

! Can  the  flow  through  the  clarifiers  be  slowed  down?  !  Is  one  clarifier  being  overloaded?  

Chlorine  Control  

Natural  Organic  MaAer  

(measured  as  TOC)  

+Added  

Disinfectant   = DBP  

Required  Chlorine  Residuals  ! Maintain  at  the  Point  of  Entry  

!  no  less  than  1.0  mg/L  free  chlorine  !  no  less  than  2.0  mg/L  total  chlorine  for  chloramines  systems  

!  no  greater  than  4.0  mg/L  (RAA)  free  or  total  chlorine  

! Maintain  in  the  Distribution  System  !  System  no  less  than  0.2  mg/L  free  chlorine  

!  System  no  less  than  1.0  mg/L  total  chlorine  for  chloramines  systems    

OUT

Secondary Cl2 = 2 ppm

Cl2= 3.2 ppm

IN PUMP

Maximize  CT  –  Minimize  DBP’s  Add  the  chlorine  needed  to  achieve  at  least  0.5  log  removal  of  Giardia,  add  the  rest  downstream.  

Cl2= 1.2 ppm

POE  Free  Chlorine  Residual  Modifica(on  

! The  minimum  free  chlorine  residual  at  the  POE  shall  be  at  1.0  mg/l.  For  supplies  that  document  they  meet  or  exceed  the  inactivation  requirements  in  OAC  252:631-‐3-‐3(a)(1),  the  minimum  free  chlorine  residual  at  the  POE  shall  be  0.2  mg/l.    

       -‐  OAC  252:631-‐3-‐3(d)(2)    

OUT

Secondary Cl2 = 2 ppm Cl2= 2.5 ppm

IN PUMP

Maximize  CT  –  Minimize  DBP’s  Add  the  chlorine  needed  to  achieve  at  least  0.5  log  removal  of  Giardia,  add  the  rest  downstream.  

Cl2= 0.5 ppm

Modification   Potential  Benefits   Potential  Issues  

Enhanced  Coagulation  

•  may  improve  disinfection  effectiveness  •  can  reduce  bromate  formation  by  reducing  pH  •  can  reduce  DBP  formation  

•  may  adversely  impact  finished  water  turbidity  •  lower  pH  can  cause  corrosion  problems  •  may  see  increased  inorganics  concentrations  in  finished  water  •  issues  with  disposal  of  residuals  

Decreasing    pH   •  same  inactivation  can  be  achieved  with  lower  disinfectant  dose  or  shorter  free  chlorine  contact  time  •  lower  pH  may  reduce  some  TTHMs  

•  may  increase  HAA5  •  can  adversely  affect  treatment  plant  equipment  •  may  impact  settling  and  sludge  dewatering  •  can  cause  corrosion  problems  •  may  be  difficult  to  maintain  a  residual  

Moving  the  Point  of  Chlorination  Downstream  

•  reduces  DBP  concentrations  •  reduces  amount  of  disinfectant  used    

•  May  impact  ability  to  meet  CT  requirements  •  provides  less  effective  treatment  for  iron  or  manganese    

Conclusion  ! PWS  will  find  improving  and  optimizing  current  operations  is  the  best  first  step  when  making  changes  to  achieve  compliance.  ! No  major  capital  improvements.  ! Operators  are  already  familiar  with  the  processes.  ! Operational  improvements  could  lead  to  less  expensive  or  simpler  technologies  

!  Adding  new  technology  may  not  have  the  desired  effect  if  existing  technologies  aren’t  optimized.  

Representative  Ext.  Kay  Coffey    8145  (Manager)  Shane  Hacker  8108  Steven  Hoffman  8143  (Team  Leader;  AWOP)  Dawn  Hoggard  8149  Dave  Mercer  8147  Zach  Paden    8106  Brian  Schwegal  8105  Candy  Thompson  8103  *  District  assigned  by  color  code    Administrative  Assistant  Ramona  Haggins  8107  

Interim  *  

Brian  S.  

Haskell  

Latimer  Le  Flore  

Choctaw   McCurtain  

Pushmataha  

Bryan  

Atoka  

Kingfisher  

Canadian   Oklahoma  

Blaine  Logan  

Public  Water  Supply  Sec(on    District  Assignments  (May  20,  2014)  

Cleveland  

Mcclain  

Johnston  

Stephens  

Love  

Carter  

Garvin  

Murray  

Marshall  

Zach  P.  Custer  

Dewey  

Major  

Beaver  Cimarron  Harper  Texas   Woods  

Woodward  

Ellis  

Roger  Mills  

Alfalfa   Grant  

Candy  T.  

Sequoyah  

Cherokee  

Creek  

Mayes  Rogers  

Tulsa  

Okmulgee  

Wagoner  

Muskogee  

Hughes  Pittsburg  

Coal  

Pontotoc  

Garfield  

Payne  

Kay  

Noble  

Osage  

Pawnee  

Pottaw

atom

ie  

Seminole  

McIntosh Okfuske

e  

Lincoln  

Was

hing

ton  

Adair  

Craig  

Delaware  

Ottawa  Nowata  

Steven H.

Dawn  H.  

Jefferson  

Tillman  

Caddo  

Comanche  

Cotton  

Greer  

Jackson  

Kiowa  

Washita  Beckham  Grady  

Dave M.

Shane H.

Interim *

Interim *