EVALUATING OPTIONS USING THE SIMULTANEOUS COMPLIANCE MANUAL ST JOHNSBURY, VT

1
EVALUATING OPTIONS USING THE SIMULTANEOUS
COMPLIANCE MANUALST JOHNSBURY, VT

• RED DUFRESNE
• DUFRESNE ASSOCIATES
• DA ENGINEERS

2
SUMMARY AND KEY POINTS

• ORGANIZE AND ANALYZE SYSTEM DATA
• SPECIFICALLY DEFINE THE PROBLEM
• CONSIDER BOTH ALTERNATIVES IN MANUAL AND
  ALTERNATIVES YOU DEVELOP
• TRY THE MOST FEASIBLE ITEMS FIRST
• BE PATIENT - IT TAKES A YEAR TO SEE RESULTS
• DEVELOP A LONG TERM DBP REDUCTION PLAN

3
SAINT JOHNSBURY VT

• SINGLE SOURCE-SURFACE WATER
• STILES POND
• RURAL WOODED WATERSHED
• ONE SHORELINE BOUNDED BY ROUTE 18
• POND SURFACE IS 146 ACRES
• POND VOLUME 450 MG
• AVERAGE DEPTH 10 FEET
• SINGLE LEVEL INTAKE IN 10.7 FEET OF WATER

4
SAINT JOHNSBURY VT

• RAW WATER QUALITY
• TYPICAL COLOR 10 TO 20 CU (TRUE)
• TYPICAL TURBIDITY 1 TO 2 NTUS
• TOC 8 TO 10 PPM (WINTER-SUMMER)
• HARDNESS 70 TO 90 PPM AS CaCO3
• ALKALINITY 120 PPM AS CaCO3
• IRON lt0.1 PPM
• MANGANESE 0.02 TO O.3 PPM
• NO SIGNIFICANT TASTES/ODORS
• NO SIGNIFICANT ALGAL ISSUES

5
SAINT JOHNSBURY VT

• WATER TREATMENT PLANT
• PACKAGE TRIDENT
• 3 MGD CAPACITY
• RAW WATER PUMPS
• ALUM AND POLYMER (Praestol N3100 LTR)
• POTASSIUM PERMANGANATE
• CAUSTIC SODA
• FLOURIDE
• SODIUM HYPOCHLORITE
• ADEQUATE TOC REMOVAL AS PER S1D/DBP RULE

6
ST J WATER TREATMENT PLANT

• CHARACTERISTICS
• 1.4 MGD AVERAGE DAY
• 1.7 MGD MAXIMUM DAY
• SMALL CLEARWELL 145,000 MG
• OFF/OPERATION
• WASTE PROCESS WATER RECYCLE SYSTEM
• LAGOONS WITH DISCHARGE PERMIT

7
SAINT JOHNSBURY VT

• DISTRIBUTION SYSTEM
• 53 MILES OF DI OR CI PIPE
• 21.7 MILES OF UNLINED CAST IRON
• 20 MILES OF PIPE 6-INCH DIAMTER OR LESS
• CLEARWELL PLUS FIVE STORAGE TANKS
• 317 CUSTOMERS (80 RESIDENTIAL)

8
St J Water Distribution System
9
PROBLEM
10
STATE REQUIRED REPORT FOR DBP REDUCTION

• REVIEW DATA AND SYSTEM CHARACTERISTICS
• DEFINE PROBLEM
• DEVELOP AND EVALUATE ALTERNATIVE
• DEVELOP RECOMMENDATIONS
• IDENTIFY FUNDING REQUIREMENTS

11
Assemble Data

• THM and HAA data
• Feed Rates
• Free and combined residual leaving plant
• TOC and/or DOC
• Free and combined residual at total coliform
  sample sites
• System and subsystem flow

12
(No Transcript)
13
FREE CHLORINE RESIDUALS AT COLIFORM SAMPLE SITES

• Fire Station 0.6 to 1.7 mg/l
• Sewer Department 0.2 to 1.2 mg/l
• Breezy Hill Pump 0.9 TO 2.2 mg/l
• UPS Industrial Park 0.18 to 1.66 mg/l

14
Customer Complaints

• Date
• Location
• Summary of Complaint
• Conclusions
• Actions taken

15
WATER SYSTEM BASE MAP AND COMPUTER MODEL
16
Result of Water Age Analysis - Location 1
Industrial Parkway
17
Result of Water Age Analysis - Location 6
Memorial Drive (Route 5)
18
INACTIVE WATER STORAGE
19
DEFINE THE PROBLEM

• Violation of Stage 1 Disinfectants Disinfection
  Byproducts
• Consistent levels of THM between 80 and 95 ppb
• Higher than necessary chlorine residual
• But some areas with no free residual
• High Water Age in Areas of the System
• Stagnant Water Storage Tanks

20
DEFINE THE PROBLEM

• Any other factors
• No Coliform Hits
• HAAs are acceptable under the S1D/DBP Rule
• No Significant Customer Complaints
• Adequate color removal
• Adequate TOC removal

21
OBJECTIVES

• OBTAIN COMPLIANCE WITH THE S1 D/DBP RULE
• DEVELOP A PLAN TO BE IN COMPLIANCE WITH THE S2
  D/DBP RULE
• INSURE MICROBIAL THREATS ARE MINIMIZED
• MINIMIZE CAPITAL AND OPERATIONAL COSTS ON THIS
  ISSUE

22
ALTERNATIVES
23
ALTERNATIVES

• IMPROVING AND OPTIMIZING CURRENT OPERATIONS
• INSTALLING TOC OR MICROBIAL REMOVAL EQUIPMENT
• IMPLEMENTING ALTERNATI VE DISINFECTION STRATEGIES

24
IMPROVING AND OPTIMIZING CURRENT OPERATIONS

• Source Management
• Distribution System BMPs
• Move Point of Chlorination
• Decrease pH

25
IMPROVING AND OPTIMIZING CURRENT OPERATIONS

• Reduce Chlorine Dose (especially during summer
  and fall)
• Modify Pre-Sedimentation Basin Operation
• Enhanced Coagulation
• Enhanced Softening

26
TOC and/or MICROBIAL REMOVAL DEVICES

• Granular Activated Carbon
• Microfiltration or Ultrafiltration
• Nanofiltration
• Other Methods
• Bank filtration
• Improved Filter Performance
• Bag or Cartridge Filtration
• Second Stage or Series filtration

27
ALTERNATIVE DISINFECTION

• Primary Disinfection (Other than free Chlorine)
• Monochloramines
• Ozone
• Ultraviolet
• Chlorine Dioxide

28
ALTERNATIVE DISINFECTION

• Secondary Disinfection (Only two choices)
• Free Chlorine
• Monochloramine

29
Source Management

• Alternative Source Flexibility
• Intake Placement
• Location
• Vertical
• Flexibility
• Raw Water Aeration

30
Distribution System BMPs

• Water Age Management
• Mixing in Water Storage Tanks
• Decommission Storage Tanks
• Adding Pipe Interconnections
• Booster Disinfection
• Water Main Flushing
• Self Assessment

31
Other BMPs

• Pressure Zone Configuration
• Pipeline Rehabilitation
• Finished Water Storage Tank Inspection

32
Distribution BMP Challenges

• Re-suspension of Sediments
• Issues Disposing Flush Water
• Lining Materials Leaching into Water
• Less System Storage Available for Fire and
  Emergency
• Increase in Lost Water

33
BMP Results in Saint Johnsbury

• Flushing the system resulted in highest ever
  reading for TTHM
• Modeling indicates that mixing storage tanks
  would increase water age for customers near tanks

34
Other Operational Items

• Move Point of Chlorination

35
Other Operational Items

• Decreasing pH
• Reducing Chlorine Dose during Warm Water
  Temperatures
• Modify Pretreatment Basins
• Enhanced Coagulation
• Enhanced Softening

36
RESULTS FOR ST JOHNSBURY

• Decreasing pH is not an alternative
• Move Chlorination Point
• Reducing Chlorine Dose
• Pretreatment Unit Operation
• Enhanced Coagulation
• Enhanced Softening (Not an Alternative)

37
RESULTS FOR ST JOHNSBURY

• Eliminated Pre-chlorination
• Reduced Chlorine Dose

38
RESULTS FOR ST JOHNSBURY

• Alternatives not in the Guidance Manual
• Pre-oxidation with KMnO4
• Move the KMnO4 Injection Point to Intake
• Optimize Treatment Process
• Eliminate Waste Process Water Recycle
• Extend Clarifier Flush Duration
• Extend Backwash Duration
• Extend Filter to Waste Duration

39
TOC AND MICROBIAL REMOVAL EQUIPMENT

• Granular Activated Carbon
• Microfiltration
• Ultrafiltration
• Nanofiltration
• Other Methods
• Bank filtration
• Improved Filter Performance
• Bag or Cartridge Filtration
• Second Stage or Series filtration

40
Granular Activated Carbon

• Replace the Anthracite Layer with GAC
• Replace the Media with GAC
• Replace the Mixed Media Trident filter Units with
  Deep Bed GAC
• Series Filtration at two Locations
• PAC
• Not noted as a TOC Removal alternative in the
  Guidance Manual

41
GAC Issues

• Advantages
• Removes DBP Precursors
• Removes Taste and Odor
• Can Receive a 0.5 log Cryptosporidium Removal
  Credit
• Can Be Used as a BAF after ozone to remove AOC
• Disadvantages
• Previously Adsorbed Compounds can be Released
• Bacteria Growth can be Released

42
LIFE CYCLE COSTS GAC
43
Alternative Primary Disinfectants

• Free Chlorine
• Monochloramines
• Ozone
• Ultraviolet
• Chlorine Dioxide

44
ALTERNATIVE PRIMARY DISINFECTION
45
SECONDARY DISINFECTION
Monochloramines
46
SUMMARY OF ALTERNATIVES

• Source Management -More Data Required
• Raw Water Aeration?
• Sampling Plan for
• Dissolved Oxygen
• Color
• TOC
• Manganese
• Turbidity
• Algae

47
Distribution System BMPs

• Flushing Plan
• Mixing Storage Tanks
• Decommission Storage Tanks
• Add pipe Interconnections
• Clean and Line Pipes
• Booster Chlorination

48
Optimize Treatment

• Eliminate Pre-chlorination
• Add KMnO4
• Construct Larger Clearwell
• Extend Flush Duration
• Extend Backwash Duration
• Extend filter to Waste Duration
• Eliminate Recycle

49
Proposed DBP Reduction Plan

• Eliminate Pre-chlorination
• Feed KMnO4 as a pre-oxidant
• Reduce Chlorine Feed at Plant
• Boost Chlorine at Pump Station
• Construct Chlorination Booster Station for
  Consecutive System
• Begin Long Term data Collection for New Intake

50
Proposed DBP Reduction Plan

• Extend KMnO4 Feed Line to Inlet
• Abandon Alum Lagoons and Recycle System
• Build Additional Clearwell

51
What if we then cant meet the S2 D/DBP Rule?

• Switch to Monochloramines for Secondary
  Disinfection
• If this does not demonstrate compliance proceed
  with GAC Series Filtration
• If this does not demonstrate compliance proceed
  with Ozonation

52
Early Results

• Eliminated Pre-chlorination
• Initiated KMnO4
• Reduced Chlorine Dose

53
(No Transcript)
54
SUMMARY

• ORGANIZE AND ANALYZE SYSTEM DATA
• SPECIFICIALLY DEFINE THE PROBLEM
• CONSIDER BOTH ALTERNATIVES IN THE GUIDANCE MANUAL
  AND ALTERNATIVES YOU DEVELOP
• TRY THE MOST FEASIBLE ITEMS FIRST
• BE PATIENT - IT TAKES A YEAR TO SEE RESULTS
• DEVELOP A LONG TERM DBP REDUCTION PLAN