SouthWest
Water Company

What a utility needs
 to consider when
converting a system
 to surface water.



   Presented by:...
JR Reavis
SouthWest Water Company
PUBLIC OPINION




                 2
WHAT PEOPLE THINK WHEN YOU TELL
THEM THEY ARE DRINKING TREATED
 SURFACE (LAKE OR RIVER WATER)




                        ...
Public Opinion
● Most people don’t understand why they are being forced
               don t
  to convert to surface water...
WHAT NEEDS TO BE CONSIDERED?
● Why convert to surface water?
● Is there really a difference in water characteristics?
● Co...
WHY CONVERT TO SURFACE WATER?
● Your utility may be required to participated in
  a ground water reduction program (Subsid...
IN THE HOUSTON AREA SUBSIDENCE IS
 THE PREDOMINANT DRIVING FORCE
      BEHIND THE CONVERSION




                         ...
HOUSTON AREA SUBSIDENCE MAP




         http://pubs.usgs.gov/ha/ha730/ch_e/gif/E064.GIF
                                 ...
GROUNDWATER LEVELS IN THE HOUSTON
     AREA FROM 1931 TO 1970




                                    9
GENERAL
   DIFFERENCES
SURFACE vs. GROUND
      WATER




                     10
Ground Water                            Surface Water
•   Generally higher levels of          •   Generally higher level o...
COSTS
    Capital &
GENERAL OPERATING




                    12
CAPITAL COSTS
● New treatment equipment
     Installation of storage tanks, high service pumps, chemical
     feed equipme...
GENERAL OPERATING COSTS
● Increased operator presence
     Higher degree of compliance
     Higher degree of monitoring sa...
MONITORING




             15
INCREASED MONITORING TO
       MAINTAIN WATER QUALITY
● Unless mandated by special need, ground water
  facilities do not ...
Typical chemical & sampling scheme for
    a ground water system prior to
            d    t     t     i  t
         chlor...
Typical chemical application & sampling
    points when purchasing surface water
    from a wholesaler with no well water
...
Typical chemical application & sampling
 points when purchasing surface water
 from a wholesaler with a well system
      ...
THINGS TO REMEMBER ABOUT
  ONLINE MONITORING EQUIPMENT
● When used properly online monitoring
  instruments are great diag...
TREATMENT
 EXPERISE



            21
INCREASED NEED FOR TREATMENT
             EXPERTISE
           Ground Water                            Surface Water
●   M...
SYSTEM OPERATIONS




                    23
CHANGES TO SYSTEM OPERATION
● New treatment systems and system upgrades
    Operating a surface water system will require ...
Possible increases in time spent by
     operators taking additional samples
                                             ...
Possible increases in time & money spent
by chlorine and maintenance technicians
                     Old Well         Sur...
Possible increases in time and money
     spent in the distribution system
                    Old Well        Surface Wat...
CHANGES TO SYSTEM OPERATION
● Maintenance of standby well systems
    A system seldom used could be more expensive to
    ...
WATER QUALITY




                29
WATER AGE MANAGEMENT ISSUES
●   Water t
    W t storage – a ground water system may not be
                             d ...
WATER AGE MANAGEMENT ISSUES
● System flushing – Dead end flushing becomes very
  important to system water quality
● Water...
BASIC GROUND WATER OPERATION
                                                                  Well



      Elevated
    ...
BASIC SURFACE WATER OPERATION
         WHOLESALER TO END USER
                                                            ...
COMBINE THE TWO AND IT GETS
                   COMPLICATED       Well

                                                   ...
TREATMENT AND
 DISINFECTION




                35
Chloramination Breakpoint Curve

                            Understanding
                              Breakpoint
      ...
WHY CHLORAMINE DISINFECTION?
● C ’t hold a disinfectant residual i th distribution
  Can’t h ld di i f t t       id l in t...
Chlorine/Chloramine Interaction in
           the Distribution System



                           Transition
           ...
Chlorine Reaction with Water
     Chl i    R   ti    ith W t


Cl2         +    H 2O       HOCl     +       HCl

         ...
Monochloramine Formation



    HOCl       +       NH3             NH2Cl     +    H 2O

H                                 ...
DISINFECTION SCHEMES
● I order to maintain disinfection residuals i th system
  In d t         i t i di i f ti      id l i...
PUBLIC HEALTH
  CONCERNS




                42
SURFACE WATER HAS A HIGHER
  FORMATION POTENTIAL FOR FORMING
 DISINFECTION BY-PRODUCTS (DBPs) AND
              BY-
    OT...
NITRIFICATION
● Nitrification becomes a big issue when using
  chloramines
    Nitrification can impacts disinfectant resi...
Chloramine Formation and Decay




Controlling excess ammonia is a bigger issue than feeding
   ammonia because as chloram...
The Nitrification Process
                  Nitrosomonas                        Nitrobacters
                    (Ammonia-...
DEALING WITH THE
  WHOLESALER




                   47
THINGS TO REMEMBER WHEN YOU BUY
  WATER FROM A WHOLESALER THAT
 PROVIDES TREATED SURFACE WATER

● The treatment process at...
QUESTIONS:
      QUESTIONS


           JR Reavis
National Water Quality Director
   i   l       Q li     i
 SouthWest Wat...
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2009-06-25 Luncheon - What a Utility Needs to Consider When Converting a System to Surface Water

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2009-06-25 Luncheon - What a Utility Needs to Consider When Converting a System to Surface Water

  1. 1. SouthWest Water Company What a utility needs to consider when converting a system to surface water. Presented by: JR Reavis
  2. 2. JR Reavis SouthWest Water Company
  3. 3. PUBLIC OPINION 2
  4. 4. WHAT PEOPLE THINK WHEN YOU TELL THEM THEY ARE DRINKING TREATED SURFACE (LAKE OR RIVER WATER) 3
  5. 5. Public Opinion ● Most people don’t understand why they are being forced don t to convert to surface water Ground subsidence, aquifer depletion or cost ● Most customers can’t believe it could cost more If you’re not one that is being converted why should you ’ t th t i b i t d h h ld pay ● Most people assume that ground water is pristine and all surface water is of low quality and less safe to drink All drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants Surface water (source water) does have a higher potential for contaminants and th t i why the monitoring and f t i t d that is h th it i d treatment standards are higher for surface water treatment The presence of contaminants does not necessarily indicate that the water poses a health risk, that is why the EPA and TCEQ set limits on contaminants that pose a health risk Fact! Both are safe when properly treated, both are monitored to ensure public safety, both must meet rigorous drinking water standards 4
  6. 6. WHAT NEEDS TO BE CONSIDERED? ● Why convert to surface water? ● Is there really a difference in water characteristics? ● Cost Capital investments General operation ● Increased monitoring to maintain water quality ● Increased need for treatment expertise ● Changes to system operation New treatment systems and system upgrades d d Maintenance of standby well systems Staffing and licensing requirement ● Water Quality Issues Why chloramine disinfection? Water age management Water storage System flushing Disinfection schemes Higher formation potential for disinfection by-product and other by- regulated contaminants ● Relationship with your water wholesaler 5
  7. 7. WHY CONVERT TO SURFACE WATER? ● Your utility may be required to participated in a ground water reduction program (Subsidence or Conservation Districts: Harris Galveston, Fort Bend County, Lone Star, etc…) ● Demand has outstripped available ground water supply ● Ground water may contain regulated contaminants that are difficult to treat or would be more costly to treat than using an alternate surface water source (Arsenic, Fluoride, Radon, etc…) ● It’ cheaper to b It’s he pe buy water from a wholesaler te f om hole le than it is to rehab or develop new ground water sources 6
  8. 8. IN THE HOUSTON AREA SUBSIDENCE IS THE PREDOMINANT DRIVING FORCE BEHIND THE CONVERSION 7
  9. 9. HOUSTON AREA SUBSIDENCE MAP http://pubs.usgs.gov/ha/ha730/ch_e/gif/E064.GIF 8
  10. 10. GROUNDWATER LEVELS IN THE HOUSTON AREA FROM 1931 TO 1970 9
  11. 11. GENERAL DIFFERENCES SURFACE vs. GROUND WATER 10
  12. 12. Ground Water Surface Water • Generally higher levels of • Generally higher level or inorganics, low or no organics organics, inorganics less of an • Hydrogen sulfate iron, sulfate, iron issue manganese and other • Organics can cause taste, odor constituents can cause taste, and color issues odor and color problems • Higher DBP formation potential • Low DBP formation potential • Generally requires more • Historically most utilities use i i ll ili i sophisticated di i f hi i d disinfection i free chlorine to disinfect scheme, chloramine disinfection (simple disinfection scheme) is commonly used • Water age is not an less of an • Water age is a big consideration issue because most ground ssue ost g ou d (sto age a d us (storage and flushing are very ga e e y water lacks organics to exert a important) demand on chlorine • System wide management is • System wide water age required to maintain water management is less of an issue quality because water does not • More complicated treatment degrade in the system as easily needed (can change frequently • Water chemistry is relatively for multitude of reasons) simple, or at least it doesn’t • More complicated monitoring change frequently requirements, higher level of • Monitoring requirements are M it i i t operator skills required t kill i d relatively simple, less technical • Time demand on the operator is skills required to operate much higher • Operator time requirements are relatively low y 11
  13. 13. COSTS Capital & GENERAL OPERATING 12
  14. 14. CAPITAL COSTS ● New treatment equipment Installation of storage tanks, high service pumps, chemical feed equipment, instrumentation, etc… ● Modifications to existing water storage tanks Alternate fill & take points, monitoring equipment, mixers ● Improvements to existing chemical feed equipment Pump replacements, metering & monitoring equipment replacements (SCADA?) ● Piping and valve replacements In the facility and in the system Installation of system interconnects, valves, PRVs and meters ● Modifications to existing well systems Blow offs, SCADA control, monitoring, etc… (Just to insure reliability when needed.) ● Costs associated with capping abandoned wells 13
  15. 15. GENERAL OPERATING COSTS ● Increased operator presence Higher degree of compliance Higher degree of monitoring sampling Increased distribution presence ( y p (system flushing & g customer complaint response) Higher need for technical support Increased maintenance support for monitoring and chemical feed equipment ● Increased costs associated with maintaining standby well systems ● Increased chemical costs to maintain disinfectant residuals ● Increased laboratory fees associated with a higher level of monitoring g ● Increased costs associated with purchasing surface water ● Increased need for system flushing 14
  16. 16. MONITORING 15
  17. 17. INCREASED MONITORING TO MAINTAIN WATER QUALITY ● Unless mandated by special need, ground water facilities do not require extensive online monitoring ● Surface water plants have specific grab and online monitoring requirements in order to maintain regulatory compliance ● Repump stations may require online monitoring to insure water quality ● Whether being treated or repumped, surface water requires more extensive process monitoring to insure water quality ● Operators will need a higher level of treatment knowledge to deal with the more complicated treatment issues associated with surface water ● Process monitoring is the best tool the operator has to address problems before they become big issues 16
  18. 18. Typical chemical & sampling scheme for a ground water system prior to d t t i t chloramine conversion 1 - Free chlorine sample in the plant Sample Cl2 GST Distribution Well 17
  19. 19. Typical chemical application & sampling points when purchasing surface water from a wholesaler with no well water being used g 4 - Free chlorine samples in the plant 4 - Total chlorine samples in the plant 4 – Monochloramine samples in the plant 4 – Free ammonia samples in the plant Sample Sample Sample Sample NH3 Cl2 Cl2 NH3 Purchased GST Water (chloraminated ) Distribution 18
  20. 20. Typical chemical application & sampling points when purchasing surface water from a wholesaler with a well system being used 5 - Free chlorine samples in the plant 5 - Total chlorine samples in the plant 5 – Monochloramine samples in the plant 5 – Free ammonia samples in the plant Sample Sample Sample Cl2 Cl2 NH3 NH3 GST Distribution Well Sample Sample NH3 Cl2 Purchased Water (chloraminated ) 19
  21. 21. THINGS TO REMEMBER ABOUT ONLINE MONITORING EQUIPMENT ● When used properly online monitoring instruments are great diagnostic tools ● Online monitoring equipment is only as good as the maintenance performed on them ● Caution should be used when online monitoring equipment is used to control chemical feed equipment Online equipment fails and often generate false data Total reliance upon online monitoring equipment l l l without operator input will result in catastrophic treatment failure Online monitoring equipment can not replace operator knowledge A good operator always assumes the online equipment is wrong Verify! Verify! Verify! wrong. 20
  22. 22. TREATMENT EXPERISE 21
  23. 23. INCREASED NEED FOR TREATMENT EXPERTISE Ground Water Surface Water ● Most ground water operators ● Because of the organic nature have long term familiarity with of surface water, quality the ground water operation but changes can occur frequently in lack familiarity with surface a surface water system water treatment issues making ● It is often hard to diagnose the technical support a necessity problem because of the ● Few changes occur from day-to- complexity of the source water day in ground water quality (What worked the previously ● Ground water lacks the organic may not work this time) constituents that create ● Treatment needs change with constantly changing treatment the seasons or weather needs conditions ● Once a successful treatment ● The distribution system is more scheme is determined it is biologically active and needs to seldom changed be addressed accordingly ● Problems associated with DBP ● DBP formation potential is more formation are less likely with likely due to the presence of water that contains little or no organics in the source water organic material ● More extensive regulatory compliance requirements than those required for ground water Diagnosis and reaction to treatment issues quickly are crucial for systems using surface water! 22
  24. 24. SYSTEM OPERATIONS 23
  25. 25. CHANGES TO SYSTEM OPERATION ● New treatment systems and system upgrades Operating a surface water system will require the addition of numerous new chemical feed systems: coagulant, polymers, ammonia, pH adjustment systems, oxidants (KMnO4, chlorine dioxide, ozone), fluoride, etc… Higher number of feed systems will require greater operator knowledge and skills in order to make chemical dosages changes and perform monitoring tests Higher importance needs to be placed on equipment maintenance – E i Equipment redundancy i a must d d is – The system should have a managed maintenance system to track routine, corrective and emergency repairs, as well as manage parts inventory – B d Budgeting for equipment replacement and reconditioning i f i l d di i i is even more important due to the number of equipment items and the importance that each item has in the performance of the plant – Maintaining monitoring equipment will require more time and expertise on the maintenance staff 24
  26. 26. Possible increases in time spent by operators taking additional samples *Surface Old Well *Surface Water Water with Systems Only Well Water Supplement S l t Free Chlorine 2 @ 30 sec each 4 @ 30 sec each 5 @ 30 sec each 5 @ 1 min 30 Total Chlorine na 4 @ 1 min 30 sec each sec each Monochloramine/ na 4 @ 12 min each 5 @ 12 min each Free Ammonia Sample 2 @ 5 minutes 4 @ 5 min each 5 @ 5 min each Collection Time Sample Reruns 1 @ 30 sec each 2 @ 15 min each 2 @ 15 min each Total Time ~ 1 Hours ~ 2 Hours ~ 12 minutes Required 46 minutes 5 minutes *Although the operator will not always be required to sample all location, if problems exist the operator will be doing at least the number of samples listed above. This estimate does not include time spent checking chemical feed systems. 25
  27. 27. Possible increases in time & money spent by chlorine and maintenance technicians Old Well Surface Water Only or Surface Water Systems with Well Water Supplement (None) (Two or more) On- On-line Chlorine Generally done Most systems will have 1 on both the Analyzer by grab sample incoming surface line and the outgoing line (None) (Possibly two or more) Monochloramine It wasn’t Most systems will have 1 on both the / Free Ammonia necessary incoming surface line and the outgoing line Inspections and calibrations are part of Surface Flow (None) routine maintenance (an expense to the Meter/PRVs district) Chemical (Possibly as many as six) (One) metering Depending on configuration, 3 units for each Chlorinator devises ammonia and chlorine Each additional piece of equipment will require additional time on the part of the maintenance staff. Example: Each of the monochloramine/ammonia analyzers could require as much as 3-5 hours a week for the operator/maintenance staff. 3- In addition, $3,000 to $4,500 annually should be budgeted for its use (reagents, parts, required routine maintenance and possible replacement). 26
  28. 28. Possible increases in time and money spent in the distribution system Old Well Surface Water Only or Surface Water Systems with Well Water Supplement (required Based on need, it is possible that the minimum) system could require as much as 2 to 3 Flushing Dead ends times as much flushing to maintain water once/month quality. ( (most p probably y THM, HAA5, HPC, nitrite, nitrate and Monitoring M i i none) ammonia samples will need to run on the i l ill d h samples for incoming water, at the high service pumps It wasn’t operational and in the system. The frequency will range necessary purposes from weekly to monthly depending on conditions within the system. (none) The only way monitoring samples will be of use is if they are easily tracked and Monitoring Generally only available when needed. It is also one of the sample compliance only tools the client has to address issues y recordkeeping dk i samples are l with water quality coming from the tracked wholesale supplier. Flushing is a real cost that is realized by the district. More importantly monitoring samples necessary to operate the system properly will be additional expenses that the district will incur to insure water quality. Don’t forget to budget for maintaining standby well systems! 27
  29. 29. CHANGES TO SYSTEM OPERATION ● Maintenance of standby well systems A system seldom used could be more expensive to maintain than one that is used on a routine basis Exercising on a routine basis is a must to insure reliability ● Staffing and licensing requirement A more complicated system requires a higher degree of skill on the part of the operator Scarcity and competition f skilled operators will S it d titi for kill d t ill drive the cost of operation up You can’t expect to staff a repump station or surface water plant the same as a ground water system t l t th d t t considering the added in plant and system operating requirements 28
  30. 30. WATER QUALITY 29
  31. 31. WATER AGE MANAGEMENT ISSUES ● Water t W t storage – a ground water system may not be d t t tb configured properly to manage water age in the storage tanks because historically most storage facilities were designed to: Equalized demands Reduce pressure issues in the system Provide a reserve for fire fighting or other emergencies ● Ground water operating strategy of “keep it full at all times in case of emergency” is no longer a wise operating strategy Deep cycling storage tanks becomes very important It is possible that existing storage tanks will need modifications Baffles, mixers, tank inlets and outlets changed Elevated storage tanks can be a big concern and need to be managed to p g prevent aged water p g problems 30
  32. 32. WATER AGE MANAGEMENT ISSUES ● System flushing – Dead end flushing becomes very important to system water quality ● Water containing organics (surface water) will experience chlorine decay more rapidly than systems p y p y y using ground water ● Customer complaints need to be tracked to determine where problems are occurring (don’t assume dead ends are the only problem areas) ● Tracking water quality parameters such as taste, odor, HPCs, chlorine residual, nitrite, nitrates and free ammonia are very important ● Auto flushers will help control low chlorine residuals, taste and odor complaints and to reduce operator time in the field ● Maintenance of the complete system is more important Treatment problems don’t stop at the facility fence Treatment problems are not self correcting 31
  33. 33. BASIC GROUND WATER OPERATION Well Elevated Storage Cl2 Well Pump Ground Storage Well Elevated Storage Storage Cl2 Cl2 Cl2 Pump Pump Ground Storage 32
  34. 34. BASIC SURFACE WATER OPERATION WHOLESALER TO END USER Flocculation Bar Sedimentation Filters Rapid Pre- Pre- Screen Mix RAW Sedimentation S di t ti SOURCE Chemical Bld Initial treatment 1st Cl2 - 2nd NH3 Booster treatment Chemical Feed NH3 1st NH3 - 2nd Cl2 Cl2 Repump Pump Storage Storage Cl2 NH3 NH3 Cl2 NH3 Cl2 Repump Storage 33
  35. 35. COMBINE THE TWO AND IT GETS COMPLICATED Well Flocculation Elevated Bar Sedimentation Filters Storage Rapid RAW Pre- Pre- Screen Cl2Mix Sedimentation S di t ti SOURCE Well Pump Ground Storage Well Chemical Bld Initial treatment Elevated 1st Cl2 - 2nd NH3 Storage Storage Cl2 Booster treatment Chemical Feed Cl2 Cl2 NH3 1st NH3 - 2nd Cl2 Cl2 Repump Pump Storage Storage Pump Pump Ground Cl2 Storage 3 NH NH3 Cl2 NH3 Cl2 Repump Storage 34
  36. 36. TREATMENT AND DISINFECTION 35
  37. 37. Chloramination Breakpoint Curve Understanding Breakpoint Chemistry is Ch i t i Critical! Chlorine destroyed by reducing compounds Some Trichloramines 9:1, Cl2:NH3-N , 36
  38. 38. WHY CHLORAMINE DISINFECTION? ● C ’t hold a disinfectant residual i th distribution Can’t h ld di i f t t id l in the di t ib ti system Free chlorine is a stronger disinfectant that quickly reacts with anything that will oxidize THMs (a regulated disinfection by-product) rapidly form in the by- presence of free chlorine and organics In the presence of organics the free chlorine disinfectant residual is quickly consumed Chloramines are a weaker disinfectant but more stable than chlorine Weaker, Less reactive disinfectant, that is why is it not used as the primary disinfectant in water treatment, but when used in conjunction with a stronger disinfectant it is very effective j g y Provides a higher residual in the distribution system ● In some cases a utility may want to convert to chloramine disinfection even though they are not converting to surface water Utilities that frequently use an emergency interconnect with a neighboring system that does utilizes chloramine disinfection in their distribution system You will have problems in the distribution if you try to operate a system using both chlorine and chloramines 37
  39. 39. Chlorine/Chloramine Interaction in the Distribution System Transition Zone Fewer Very Fewer Customer Unhappy Customer From Complaints Customers Complaints Well Water Wholesaler Good Low Good or System with Chlorine Chlorine Chlorine us g ee using Free Chloramines Chl i Residuals Residuals Residuals Chlorine Bad Taste & Odor Issues High Levels of DBPs ● You can’t run a system with chlorine and chloramines simultaneously because it creates a transition zone with very unhappy customers. customers. ● Depending on system pressures, the transition zone can move. move. You can tell this by monitoring customer complaints. complaints. 38
  40. 40. Chlorine Reaction with Water Chl i R ti ith W t Cl2 + H 2O HOCl + HCl H H O H Cl Cl + O Cl + Cl H Chlorine + Water Hypochlorous Acid + Hydrochloric Acid 39
  41. 41. Monochloramine Formation HOCl + NH3 NH2Cl + H 2O H H O H N H Cl + H N H Cl + O H H Hypochlorous hl Acid + Ammonia Monochloramine + Water 40
  42. 42. DISINFECTION SCHEMES ● I order to maintain disinfection residuals i th system In d t i t i di i f ti id l in the t chloramines may need to be used ● Systems using both ground water and surface water must use the same disinfection scheme ● In order to avoid problems, systems that routinely rely on interconnects with other systems will need to conform to the same disinfection schemes used by the supplier ● Chlorine chemistry becomes critical when using chloramines Ratios, dosages and feed rates significantly impact formation potential of DBPs Loss of the chlorine or ammonia feed system even for a short period of time can become a significant compliance problem System monitoring, both grab and online monitoring is monitoring vitally important Without adequate monitoring there is no way to avoid water quality issues 41
  43. 43. PUBLIC HEALTH CONCERNS 42
  44. 44. SURFACE WATER HAS A HIGHER FORMATION POTENTIAL FOR FORMING DISINFECTION BY-PRODUCTS (DBPs) AND BY- OTHER REGULATED CONTAMINANTS ● The difference, ground water lacks organics and the difference potential to form DBPs DPB formation is impacted by: Nature and quality of the source water q y Chlorine/chloramine concentrations Chlorine to ammonia ratio Temperature Contact time (water age) Cryptosporidium and Giardia are biological contaminants that most ground water systems would never deal with Both are naturally present in the intestines of most mammals including humans, and are passed into the environment through urban runoff or sewage disposal system failure 43
  45. 45. NITRIFICATION ● Nitrification becomes a big issue when using chloramines Nitrification can impacts disinfectant residuals and general water q g quality y Many of the same issues that impact DBP formation impact the nitrification process Nature and quality of the source water Chlorine/chloramine concentrations Chlorine to ammonia ratio Temperature Contact time (water age) C t t ti ( t ) Nitrification is not a self correcting issue, it can’t be ignored The best treatment strategy is to monitor, control monitor ammonia levels and reduce water age And don’t forget, it draws the attention of the regulators 44
  46. 46. Chloramine Formation and Decay Controlling excess ammonia is a bigger issue than feeding ammonia because as chloramines decay ammonia is released to be reused, either to form more chloramines or as a food source for nitrifying bacteria. Source: http://www.tawwa.org/TW07Proceedings/070412a/WaterTreatment/The%2 0Ties%20That%20Bind.pdf 45
  47. 47. The Nitrification Process Nitrosomonas Nitrobacters (Ammonia- (Ammonia- (Nitrite- (Nitrite-Oxidizing Oxidizing Bacteria) Bacteria) Ammonia Nitrite Nitrate (NH3) (NO2-) (NO3-) Optimum Conditions Influencing Factors pH 7.5 – 8.5 Water Temperature Temp. 25 - 30°C 30° Detention Time Free Ammonia Excess Ammonia Dark Environment Chloramine Concentration Early Warning Signs Prevention and Control Decrease in Ammonia Decrease Detention Time Decrease in Chlorine Decrease Free Ammonia Decrease in pH Increase Disinfection Dosage Increase in Nitrite Ratio Increase in HPC Breakpoint chlorinate Establish a Flushing Program Source: Small system Operation and Maintenance (Ken Kerry) 46
  48. 48. DEALING WITH THE WHOLESALER 47
  49. 49. THINGS TO REMEMBER WHEN YOU BUY WATER FROM A WHOLESALER THAT PROVIDES TREATED SURFACE WATER ● The treatment process at the wholesaler plant is critical If they get it wrong, it’s wrong everywhere If they have problems, you have problems If the wholesaler has formed DBPs, you can t remove them DBPs can’t easily or cost effectively ● Caution! Don’t assume that anytime there is a water Caution! quality problem it is the wholesalers fault because each time water is re-chloraminated, or simply given enough re- time, the possibility that problems can occur increases ● Process control monitoring system entry monitoring monitoring, and communication with your wholesaler are the best tools you have to insure purchased water quality 48
  50. 50. QUESTIONS: QUESTIONS JR Reavis National Water Quality Director i l Q li i SouthWest Water Company 281-216- 281-216-3545 jrreavis@swwc.com 49

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