VILLAGE OF WEST DUNDEE, ILLINOISWATER SYSTEM INVESTIGATION

HIGH PRESSURE ZONE WATER QUALITY

Presentation to the Village Board

August 19, 2013

WATER QUALITY INVESTIGATION

• THE WATER PRODUCED BY THE RANDALL

ROAD WATER TREATMENT PLANT MEETS

ALL IEPA STANDARDS AND IS SAFE TO

DRINK

WATER QUALITY INVESTIGATIONPURPOSE OF INVESTIGATION

• Discover source of poor water quality and low

chlorine residuals in several areas within the

distribution system

– Particularly area west of Tartan Dr. in Village’s

High Pressure Zone.

• Determine more accurate cost of ozone

system and if it is the most cost effective

solution.

WATER QUALITY

INVESTIGATIONLocations of Complaints

WTP & 1.0

MG Tank

WATER QUALITY INVESTIGATIONPROJECT HISTORY

WATER QUALITY INVESTIGATIONINVESTIGATIVE PROCESS

WATER QUALITY INVESTIGATIONReport Findings

WATER QUALITY INVESTIGATIONReport Findings

WATER QUALITY INVESTIGATIONReport Findings

WATER QUALITY INVESTIGATIONReport Findings

WATER QUALITY INVESTIGATIONReport Findings

WATER QUALITY INVESTIGATIONReport Findings

• SRB’s are “anaerobic” and not harmful to

humans.

– SBR bacteria dies when exposed to oxygen in the

air or water

• SRB’s can protect themselves from low

chlorine residuals and oxygen by hiding in silt

and sediments in the bottom of water mains.

– High chlorine residuals can control SRB’s but not

eliminate them.

WATER QUALITY INVESTIGATIONReport Findings

• Every community must deal with sediment

in mains – no one is exempt

– This includes Lake Michigan Water supplies and

– Well based supplies

• Most conduct flushing programs once or

twice each year.

WATER QUALITY INVESTIGATIONRecommendations

A mixing system needs to be installed in

the tank to keep the water mixed and to

allow additional chlorine to be added if

it becomes necessary.

TANK CLEANING

& MIXING SYSTEMThe existing elevated tank interior needs

to be cleaned by power washing and

disinfection to ensure the tank is not

contributing to SBR growth.

WATER QUALITY INVESTIGATION“Tank Mixing System”

(Cl2 can be added

if necessary)

1.0 MG

Tank

Circulation Pump

In base of tank

To

Distribution

System

From

Water Treatment

Plant

150 gpm

WATER QUALITY INVESTIGATION“Split Pre-Chlorination”

Barium Removal

SofteningClearwell

Distribution

System

Cl2(H2S & Disinfection)

Cl2(Residual)

Current

Sulfate

Well 6

1.0 MG

Tank

(Sulfate)

(Ba & H2S)

WATER QUALITY INVESTIGATION“Split Pre-Chlorination”

Barium Removal

SofteningClearwell

Distribution

System

Cl2(H2S & Disinfection)

Cl2(Residual)

Current

Sulfate

Well 6

1.0 MG

Tank

Barium & Sulfate

Removal

SofteningClearwell

Distribution

System

Proposed

Cl2(Disinfection)

Cl2(Residual)

Cl2(H2S)

(Cl2)?

Well 6(BaSO4)

1.0 MG

Tank

Circulation

(Sulfate)

(Ba & H2S)

(Ba & H2S)

WATER QUALITY INVESTIGATION“Water Main Cleaning”

• Water mains need to be cleaned.

• The only way to ensure that SBR activity

continues to be reduced or eliminated is to

remove the SBR’s in the residual silt and

sediment on the bottom of the existing

large diameter mains.

WATER QUALITY INVESTIGATION“Water Main Cleaning”

• Flushing alone will not remove the silt, sediment, and SBR’s from the mains as the mains are designed to convey large quantities of water to meet fire suppression needs with low headloss (low velocity).

• Mechanical removal by “pigging” or “ice-pigging” is the only way to remove the majority of the silt and sediment.

Ice-pigging is more economical because

the system uses existing hydrants and

does not require excavation to install pig

“launchers” or “receivers”.

Ice-pigging uses treated water, the

equivalent of table salt, and refrigeration

to create a “slushy” which is pumped

through the existing mains to remove silt

and sediment. No hazardous chemicals

are used.

ICE PIGGING

WATER QUALITY INVESTIGATION“Ice-Pigging”

WATER QUALITY INVESTIGATION“Automatic Flushing Stations”

WATER QUALITY INVESTIGATION“Automatic Flushing Stations”

WATER QUALITY INVESTIGATIONSummary

Recommendation Estimated Cost

Install temporary elevated tank mixing system $ 7,000

Install hydrogen sulfide pre-chlorination system in water

treatment plant $ 30,000

Install permanent tank mixing system $ 60,000

Install Automatic Flushing Stations

Hilly Lane $ 35,000

Wesemann Drive $ 35,000

Use pigging, scouring, or ice pigging in areas of low demand

and large water mains to remove sediment from existing

water mains. $120,000

WATER QUALITY INVESTIGATIONSummary

BENEFITS

Proposed

Improvements

($357,000¹)

Ozone System

($645,500²)

Destroys H2S in Water from Well No. 6 X X

Remove Sulfate from water by precipitating barium X X

Reduce Chlorine Demand at WTP No Change X

Reduce Ferric Sulfate used in barium removal system X X

Elevated Tank Mixing System to Improve Water Quality X

Boost Chlorine in Elevated Tank if Required X

Automatic “flushing systems” to maintain Cl2 Residual X

Clean Large Mains to remove SBR's, Silt, & Sediment X

Help Reduce Potential of DBP Formation in Water Mains X

Reduce complaints due to H2S produced in Water Mains X

Reduce Staff time Flushing Water Mains X

Reduce Chlorine Demand in Distribution System Probable

¹ Includes $287,000 (construction), plus Contingency, Design Engineering, and Permitting

² Cost includes; $595,000 (construction), plus Contingency, Design Engineering, and Permitting ($50,500)