Basic Ground Water
Treatment
Cindy Sek
Sanitary Engineer 2
DPH - Drinking Water Section
Compliance Regions - North
Drinking Water Section
Topics of Discussion
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Why is water treatment used?
ANSI/NSF Standards
Considerations before installing treatment
Disinfection
Organics removal
Iron and manganese removal
Corrosion control treatment
Treatment systems in combination
General Water Treatment Guidelines
Classification of Water Treatment Plants
Drinking Water Section
Why is Water
Treatment Used?
 To remove contaminants and achieve
compliance with a Maximum Contaminant
Level (MCL) thereby reducing health risk
 Disinfection to kill or inactivate total coliform
and/or E.coli bacteria and associated
microbial pathogens
 Organics removal with Granular Activated
Carbon (GAC)
Drinking Water Section
Why is Water
Treatment Used?
 To achieve aesthetic water quality
standards
 Sediment filters to remove suspended
particles
 Ion exchange water softener
 Iron and manganese filtration
 Taste and odor control using Granular
Activated Carbon (GAC)
Drinking Water Section
Why is Water
Treatment Used?
 For corrosion control
 Calcite filtration for pH adjustment
 Chemical injection for pH adjustment
 Orthophosphate for sequestering
Drinking Water Section
ANSI/NSF Standard 60 & 61
 All drinking water treatment chemicals and
components must be certified to ANSI/NSF
standards.
 NSF/ANSI Standard 60: Drinking Water Treatment
Chemicals - Health Effects is the nationally
recognized health effects standard for chemicals
which are used to treat drinking water.
 NSF/ANSI Standard 61: Drinking Water System
Components - Health Effects is the nationally
recognized health effects standard for all devices,
components and materials which contact drinking
water.
Drinking Water Section
Other ANSI/NSF Standards
 NSF/ANSI Standard 42: Drinking Water
Treatment Units - Aesthetic Effects
 NSF/ANSI Standard 44: Cation Exchange Water
Softeners
 NSF/ANSI Standard 53: Drinking Water
Treatment Units - Health Effects
 NSF/ANSI Standard 55: Ultraviolet Microbiological
Water Treatment Systems
 NSF/ANSI Standard 58: Reverse Osmosis
Drinking Water Treatment Systems
 Visit www.nsf.org for more information
Drinking Water Section
Considerations Before
Installing Treatment
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Type and concentration(s) of contaminant(s)
Treatment options
NSF Certification
Initial cost of installing treatment equipment and ongoing
costs of maintenance, chemicals, and additional water
quality testing
 Available room to install treatment in existing pump house
 Submittal to DPH for review and approval prior to
installation per RCSA Section 19-13-B102(d)(2)
 Water treatment plant operator to maintain and operate the
treatment system
 Staff certified at the appropriate level
 Contracting with a certified treatment plant operator
Drinking Water Section
Chemical Disinfection
 Chlorination is used to inactivate bacteria and/or viruses that
may be introduced into the water system
 Correct well violations and deficiencies first
 Eliminate cross connections within system piping first
 Use alternate source of supply
 GWR requires maintaining 4-log virus treatment
 Source with significant deficiency or fecal contamination
 Exempt from GWR source water monitoring requirement
 Existing treatment systems need to demonstrate that treatment meets
this level
 A CT value of about 6 is necessary to achieve this level
 Routine compliance monitoring is required to ensure that
treatment is effective and public health is protected.
Drinking Water Section
Compliance Monitoring
 Chlorine Compliance monitoring
 >3,300 population – continuous monitoring
at a location at least equivalent to 1st
customer.
 <3,300 population – continuous monitoring
at a location equivalent to 1st customer or 1
grab sample/day at the time of peak hourly
flow.
Drinking Water Section
 http://www.epa.gov/safewater/disinfection/gwr/compliancehelp.html
under GWR Contact Time (CT) Calculator
Drinking Water Section
Treatment
EPA CT Value Table
Drinking Water Section
Chemical Injection Systems
4-log treatment systems must have redundancy
or backup equipment immediately available.
Drinking Water Section
Chlorination Systems
Advantages
 Destroy bacteria, viruses, and other pathogenic
microorganism, except Giardia and Cryptosporidium
 Provide a barrier of protection throughout the water
system when an adequate chlorine residual is
maintained
 Disinfectant residual can be monitored
 Can be used as an oxidant to suspend metals in
solution for better filtration treatment performance
 Oxidizes hydrogen sulfide to reduce nuisance odor
Drinking Water Section
Chlorination Systems
Disadvantages
 More maintenance
 Chemical addition and disinfection by-products
 Need to maintain adequate contact time for effective
disinfection
 Need to monitored on a daily basis
 Requires a higher certified operator skill level
 More space required for contact tank and treatment
system
 Mineral oxidation may necessitate the need to install
filtration treatment if raw water has mineral content.
 Iron and/or Manganese common in groundwater
Drinking Water Section
Trivia Questions
 The GWR requires what level of treatment at the
entry point for effective virus inactivation / removal?
4-log
 Can I continue to use my existing disinfection
treatment if it does not meet 4-log virus inactivation /
removal?
Yes, however please note assessment or triggered
source water monitoring may be required.
Drinking Water Section
Ultraviolet Disinfection
 May be considered for approval as a primary
disinfection treatment if UV treatment guidelines
are met
 Source of supply is groundwater
 Bacteria (total coliform) is documented to be coming from
the groundwater source (not in distribution system)
 UV unit meets ANSI/NSF 55 Standards
 Raw water meets prerequisite water quality data
 Iron and Manganese, color, turbidity
 Suspended solid, hardness, hydrogen sulfide
Drinking Water Section
Ultraviolet Disinfection
Advantages
 No chemicals
 Instantaneous bacteria inactivation
 Closed system
 No disinfection by-products
 Low maintenance
 Can be installed in a relatively small space if
pre-treatment is not necessary
 Relatively low initial and maintenance costs
compared to chlorination systems
Drinking Water Section
Ultraviolet Disinfection
Disadvantages
 No disinfectant residual.
 Currently, no known single low pressure UV units will
provide 4-log inactivation/removal of viruses.
 Require for assessment monitoring per GWR.
 Will only be effective if the bacteria source is entering
the water system prior to the UV unit.
 Pretreatment may be necessary for raw water with
moderate to high mineral content.
 May require units to be installed in parallel if water
system cannot be shut down to allow for UV
maintenance or replacement.
Drinking Water Section
Ultraviolet Disinfection
Drinking Water Section
Ultraviolet Disinfection
Drinking Water Section
Trivia Question
 What are some of the raw water
minerals to be concerned of when
considering a UV treatment system?
Drinking Water Section
Trivia Question
 What are some of the raw water minerals to be
concerned of when considering a UV
treatment system?
Parameter
Maximum Limit
Color
15
Iron
0.3 mg/L
Manganese
0.05 mg/L
Hardness
120 mg/L
Hydrogen Sulfide
Non-Detectable
Suspended Solids
10 mg/L
Turbidity
1.0 NTU
Drinking Water Section
Granular Activated Carbon
(GAC)
 Absorbs Organic Chemicals
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gasoline, benzene, toluene
DDT, PCB, etc.
 Controls taste & odor
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Chlorine smell
Sulfur odor (rotten egg smell)
 Typically 2 units are installed in series for
organic removal
Drinking Water Section
Multiple
GAC units
for VOC
removal
Drinking Water Section
Aeration
(Air Stripping)
Multi-Staged Bubble System
 VOC
 Radon
 TTHM
 Hydrogen Sulfide
 Iron Oxidation
pH Adjustment
Lowry Deep Bubble Air Stripper, www.lowryh2o.com
Drinking Water Section
Iron/Manganese Removal
 Filtration is typically combined with pre-oxidation
 Media: Manganese Greensand, Birm, Multimedia
 Regeneration / Oxidation: Potassium permanganate
 Oxidation: Chlorine, Air injection
 Manganese is typically oxidized at a higher pH
therefore pH adjustment may be required
 Phosphate – sequestering iron
 Water softeners
 Best for Ferrous Iron < 5 mg/L
Drinking Water Section
Iron/Manganese Removal
Continuous Regeneration
National Environmental Training Association, Inc.,
Field Guide, III-3, 1999
Drinking Water Section
Iron/Manganese Removal
Intermittent Regeneration
National Environmental Training Association, Inc.,Field Guide, III-3, 1999
Drinking Water Section
Multiple Greensand Filters
with GAC
Drinking Water Section
Trivia Question
 What is the purpose of air injection or
aeration in the treatment process?
 Oxidation
 VOC removal
 Radon removal
 pH adjustment
Drinking Water Section
Water Softeners
 Removal of hardness
 Calcium and/or Magnesium
 Removal of iron and manganese
 Regenerate with sodium chloride or
potassium chloride
 If sodium levels are already elevated,
potassium chloride may be preferable
 Sodium notification level is 28 mg/L
Drinking Water Section
Ion Exchange Softening
National Environmental Training Association, Inc.,Field Guide,
III-6, 1999
Drinking Water Section
Cartridge Sediment Filters
 Remove silt, sediment, and
other suspended matter
 Use as pre-filter for other
treatment processes
 Sediment filter should be
changed on a regular basis
 Spare filters should be kept in
their original wrappings
 Add a tablespoon of bleach to
filter housing after filter
replacement
Drinking Water Section
Trivia Questions
 What is one of the functions of a water
softener in a treatment process?
-- Hardness removal
-- Iron and Manganese removal
 Should a cartridge filter be used for
bacteria removal?
No
Drinking Water Section
Corrosion Control
 pH adjustment
 Calcite Filter
 Chemical injection
 Introduction of corrosion control inhibitors
 Calcite filters - protect scaling in pipes
 Phosphate chemical injection - applies a
protective layer on the pipes to help prevent
corrosion
Drinking Water Section
Corrosion Control
 Evaluate source Water Quality Parameters
(WQP) results
 WQP – pH, alkalinity, calcium, conductivity,
phosphate, temperature
 Based on results, determine the most
effective treatment system
 After installation of treatment, check WQP
and saturation index at entry point to confirm
treatment effectiveness
Drinking Water Section
pH Adjustment
Calcite Filters
 A.K.A. acid neutralizers or limestone contactors
 Raise pH (typically not beyond 7.5)
 Add hardness (calcium carbonate) and alkalinity
which can be beneficial for corrosion control
 Replace filter media periodically (i.e. 6-12 months)
 Minimum weekly monitoring of pH level is required
to be taken, recorded, and retained under RCSA
Section 19-13-B102(e)(7)(N)
Drinking Water Section
Drinking Water Section
Chemical Injection
 pH adjustment with potassium carbonate, sodium
carbonate (soda ash), or hydroxide products
 Allow a wider range of pH level to be achieved
 More hazardous than a calcite filter
 Potential for chemical overfeed if chemical injection safety
controls are not installed
 Recommend injection paced proportionate to flow
 Sequestering with phosphate
 Daily monitoring of pH level or biweekly monitoring of
phosphate level is required to be taken, recorded, and
retained under RCSA Section 19-13-B102(e)(7)(N)
Drinking Water Section
Drinking Water Section
Trivia Question
 What is the monitoring requirement for
the pH adjustment process?
-- Calcite Filters - at least weekly pH readings
-- Chemical injection – Daily pH readings
The readings must be recorded on the Treatment
Effluent Log and submitted to drinking.water@ct.gov
by the 9th day of the following month.
Drinking Water Section
Treatment Systems in
Combination
 Calcite followed by a water softener
 Used to remove iron and manganese
 Calcite raises pH and facilitates manganese
removal with the water softener
 Calcite adds hardness and water softener reduces
hardness
 Water softener followed by UV Treatment
 Water softener reduces hardness, iron and
manganese
 Bacteria passing through UV unit is inactivated and
does not “hide” under larger minerals
 Many other possible combinations
Drinking Water Section
Neutralizer + Water softener +
sediment filter + UV
Drinking Water Section
Where does the backwash go?
 BACK WASH DISCHARGE MUST BE AIR-GAPPED
 Not in the septic system (definition of domestic sewage
in RCSA Section 19-13-B103 excludes treatment
backwash)
 Dedicated on-site water treatment disposal system or
sanitary sewer (Draft DEEP General Permit for the Discharge of Low
Flow Water Treatment Wastewater)
 Must meet separating distance to well
 Must be at least 10 ft from existing septic system
 DEEP General Permit may be required
 Backwash discharge > 500 GPD
Drinking Water Section
Drinking Water Section
What is wrong?
Drinking Water Section
What is wrong?
No air gap for BW discharges
No air gap for BW discharges
& storage tank drain
Drinking Water Section
Classification of
Water Treatment Plants and
Small Water Systems
Drinking Water Section
Small Water Systems
 If the CPWS or NTNC serves less than
1,000 persons and either has no
treatment or a treatment unit process
that does not require any chemical
treatment, process adjustment or media
regeneration by an operator then the
system is classified as a “SMALL
WATER SYSTEM”
Drinking Water Section
“Passive Treatment” Small Water System
 Treatment unit process that does not require any
chemical treatment, process adjustment or media
regeneration by an operator
 UV Light
 Calcite filter – media is replaced off site by
licensed professional
 Cartridge filter (whole house filter, sediment filter)
 Exchange Softener – no backwash & media is
regenerated off site
 Granular Activated Carbon (taste & odor control)
Drinking Water Section
Water Treatment Plant
Classification Form
Points Assigned for:
 Population Served
 Water Supply Source
 Chemical Treatment/Addition Process
 Coagulation & Flocculation Process
 Clarification/Sedimentation Process
 Filtration Process
 Other Treatment Processes
 Special Processes
 Residuals Disposal
 Facility Characteristics - Instrumentation
Drinking Water Section
Water Treatment Plant
Classification Form
 Add up all the points and determine which level
treatment plant applies
TREATMENT PLANT LEVEL
 Class I
30 points or less
 Class II
31 - 55 points
 Class III
56 - 75 points
 Class IV
76 points or greater
 Available on the Drinking Water Section website:
www.ct.gov/dph/publicdrinkingwater
Drinking Water Section
Treatment Plant Classification
Activity
 XYZ community public water system utilizes
two wells to serve 200 people.
 Well withdrawal rate
 8 gpm each (8,640 gpd each)
 Raw water quality
 elevated iron, manganese, color & turbidity, 5.8 pH
 Treatment Processes
 Chlorination, pH adjustment with KOH, greensand
filters with potassium permanganate (KMnO4) for
regeneration and intermittent backwash discharge
to on-site dedicated disposal system
Drinking Water Section
Drinking Water Section
This includes
the greensand
filter (5 pts) and
potassium
permanganate
(10 pts)
Drinking Water Section
Total 53 points
Class II
treatment plant
Requires a Class II
treatment plant
operator
Drinking Water Section
Contact Information
 Drinking Water Section
410 Capitol Ave, MS# 51-WAT
P.O. Box 340308
Hartford, CT 06134-0308
www.ct.gov/dph/publicdrinkingwater
Phone: 860-509-7333
Emergency Phone: 860-509-8000
Fax: 860-509-7359
Drinking Water Section