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Champlain Water District Corrosion Control Program
Champlain Water District’s (CWD) Corrosion Control Program began in 1984 and achieved optimization under the USEPA Lead and Copper Rule. CWD’s optimization activities are implemented using a framework that complements CWD’s longstanding goals. CWD is a municipal entity chartered by the Vermont Legislature to provide drinking water to member communities.
The district include 8 publicly elected commissioners, one from each member town, and it serves 75,000 people. 23 million gallons per day are modified through direct filtration-type plant in South Burlington, VT. View more information about the optimized corrosion control program (PDF).
- Clarifiers & Filters
- Treatment Plant Organization
- Historical Efforts 1984 - 1991
- Ideal Pipe Loop
- Metals Release Pilot
The system includes 3 contact adsorption clarifiers and the following 8 deep bed multimedia filters:
- Coagulation/Flocculation with adsorption clarification as pre-filtration
- Corrosion control treatment to reduce lead and copper leaching from home plumbing
- Deep Bed Multimedia Filtration for particle and natural organic material removal
- Fluoridation for Vermont Department of Health Dental Division recommendations
- pH adjustment to consistent, neutral pH
- Preoxidation/Zebra Mussel treatment
- Primary Disinfection to inactivate pathogens
- Secondary disinfection to ensure safe, effective residual throughout the distribution system, and to reduce formation of disinfection by-products
Treatment plant optimization includes the following:
- 24/7 operation of transmission/storage via SCADA system
- All SDWA sampling and reporting conducted via formal agreement dating back 25 plus years
- Combined and individual filters
- CWD compliance agent for municipal consecutive systems
- CWD ownership, operation and maintenance of infrastructure via MOUs
- CWD's source is more like a “Great Lake” than a typical low alkalinity New England source
- Further optimization lower DBP levels
- Lead service Lines (LSLs) are not present
- Target materials are 50/50 lead tin solder and brass fittings in home plumbing
- Particle Counts and turbidity
- Partnership for Safe Water
- Best of the Best Taste Awardee for North America
- Completed Phases 3 and 4 Program Requirements
- Excellence in Water Treatment Awardee - First in the Nation
Historical efforts from 1984 to 1991 (i.e. before the lead and copper rule) included:
- Based upon lab/pilot scale coupon studies and some system wide coupon insert studies
- Bench scale coupon comparisons
- Consumer location sampling (16 locations)
- Corrosion control treatment with orthophosphate started April 1987
- Investigated corrosion inhibitor which reduced rate 78%
The ideal pipe loop is a solenoid driven to simulate home water use. It uses a pilot scale to implement optimized corrosion control treatment (OCCT). The loop also accomplishes the following:
- Evaluate treatment changes on home plumbing
- Galvanic coupling of metals
- Indicated passivation of the coupons from the standpoint of metal release
- Moved to an optimized orthophosphate dose and optimized pH
- Pilot scale allows you to set conditions that may exist within consumer’s home plumbing
- Used to simulate corrosion conditions within a “typical” copper pipe system soldered with 50/50 lead tin solder
Metals release pilot (metals release monitoring) includes the following:
- As experienced during ideal pipe loop study, metals release baseline established after passivization period
- Based upon Ideal Pipe Loop concept
- Collect “first draw” 1 liter grab samples
- Continue to track passivization impact on home plumbing metal release overtime
- Use solenoid driven system to simulate home water use/materials contact times for 50 50 lead tin and brass
- Used to ensure treatment changes do not impact home plumbing