AD1 Section 331160.pdf

SECTION 331160 - DISINFECTION OF WATER STORAGE FACILITIES H2M

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PART 1 - GENERAL

1.01 SECTION INCLUDES

A. Disinfection of potable water storage facility.

1.02 REFERENCES

A. ANSI/AWWA B300 - Standard for Hypochlorites, latest revision.

B. ANSI/AWWA C652 - Standard for Disinfection of Water Storage Facilities, latest revision.

C. ANSI/AWWA C651 - Disinfecting Water Mains, latest revision.

1.03 SUBMITTALS

A. Work Plan: The Contractor shall prepare and submit for review a detailed work plan describing the disinfection and sampling process. The work pland shall include, but not limited to equipment and materials that are required, testing laboratory to be utilized, safety measures, and dechlorination process.

B. Test Reports: Indicate results comparative to specified requirements.

C. Certificate: Certify that cleanliness of water storage facilities system meets or exceeds specified requirements.

1.04 PROJECT RECORD DOCUMENTS

A. Disinfection Report Record:

1. Type and form of disinfectant used.

2. Date and time of disinfectant injection start and time of completion.

3. Test locations.

4. Initial and 24-hour disinfectant residuals (quantity in treated water) in ppm for each outlet tested.

5. Date and time of flushing start and completion.

6. Disinfectant residual after flushing in ppm for each outlet tested.

B. Bacteriological, Chemical and Organic Chemical Report Record:

1. Date issued, project name and testing laboratory name, address and telephone number.

2. Time and date of water sample collection.

3. Name of person collecting samples.

4. Test locations.

5. Initial and 24-hour disinfectant residuals in ppm.

6. Coliform bacteria and chemical test results.

7. Certification that water conforms or fails to conform to New York State drinking water standards.

8. Laboratory Director's signature and authority.

1.05 QUALITY ASSURANCE

A. Perform work in accordance with ANSI/AWWA C652.

1.06 QUALIFICATIONS

A. Water Treatment Firm: Company specializing in disinfecting potable water systems specified in this Section with minimum three (3) years experience.

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B. Testing Firm: Company specializing in testing potable water systems, approved by the New York State Department of Health.

1.07 REGULATORY REQUIREMENTS

A. Conform to Recommended Standards for Water Works and applicable codes or regulations for performing the work of this Section.

B. Water quality to conform to New York State drinking water standards after completion of disinfection.

C. The Health Department will be notified of the date of water quality testing to allow sampling by the Health Department. Provide Engineer three (3) days advanced notification of proposed sampling date.

PART 2 - PRODUCTS

2.01 DISINFECTION CHEMICALS

A. ANSI/AWWA B300, Hypochlorite.

PART 3 - EXECUTION

3.01 EXAMINATION

A. Verify that tank has been cleaned and inspected.

3.02 EXECUTION - TANK

A. Provide required equipment to perform the work of this Section. The Owner will provide the water required for the initial disinfection and filling of the tank. The Contractor shall pay for the water required for any subsequent filling of the tank based on the retail water rate.

B. Disinfect water storage facility in accordance with Method 1 or Method 2 of AWWA C652. The use of liquid chlorine is prohibited.

C. Collect samples after retention period and refilling with potable water. Samples shall not be collected if chlorine residual is greater than the typical operating residual of the water system feeding the tank, which is typically 1.0 mg/L.

D. Collect sample from tank sampling point at 2, 30 and 60 for bacteriological analysis, as listed in table 6 of Part 5, Subpart 5-1 Public Water Systems of the New York State Department of Health Water Quality Monitoring. Repeat bacteriological analysis 24 hours after initial collection.

E. Collect sample from tank sampling point at 30 minutes and have analyzed for Inorganic Chemicals (IOCs), physical characteristics, and Principal Organic Contaminants (POCs) as listed in Tables 8B, 8C, 8D, 9A, 9B, 9C and 9D of Part 5, Subpart 5-1 Public Water Systems of the New York State Department of Health Water Quality Monitoring

F. Collect sample from tank sampling point at 30 minutes and have analyzed for per- and polyfluoroalkyl substances (PFAS) by EPA Method 533 and 537.1, including PFOS, PFOA, PFBS, GenX, PFNA and all other compounds testable by these two analytical methods.

G. If water quality in tank does not meet the requirements of the Health Department for potable water, the Contractor shall re-chlorinate tank or take other steps necessary to provide

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acceptable water quality. Samples shall be collected and analyzed after each attempt at the contractors cost.

H. Neutralize residual chlorine to less than 1 mg/l with a suitable quantity of sodium bisulfite, sodium sulfide or sodium thiosulfate prior to disposal to drainage system.

3.03 EXECUTION - WATER MAIN

A. Provide required equipment to perform the work of this Section. The Owner will provide the water required for the initial filling of the piping, and valves, etc. The Contractor shall pay for the water required for any subsequent filling of these systems based on the Owner's retail water rate.

B. Prior to sampling, the required water main to be tested shall be flushed at a velocity of no less than 3.0 ft/sec. Bacteria samples may not be collected until a chlorine residual representative of the existing distribution system is achieved.

C. Collect samples 24 & 48-hours after flushing and refilling with potable water. Samples shall not be collected if a chlorine residual inconsistent with that of the existing distribution system is present. Any portion of the sample set which tests positive for total coliform and/or e-coli bacteria constitutes failure of the entire set with no exceptions.

D. Field chlorine residual checks shall be performed for each sample and shall be recorded on the laboratory sampling form for inclusion in the sampling results report.

E. Two (2) consecutive sets of bacteriological samples, taken 24 hours apart, must be collected from every 1,000 ft of new main, the end of the line and from each branch. Samples should be collected after final flushing and when the chlorine concentration in the water leaving the main is no higher than that generally prevailing in the distribution system (ANSI/AWWA C651 Standard, latest edition).

F. The water main to be tested shall include all previously installed piping from the new tank to the on-site hydrant.

3.04 QUALITY CONTROL

A. Provide analysis and testing of treated water in storage facility.

B. Test samples in accordance with ANSI/AWWA C652 and Health Department requirements.

C. Test samples for water main in accordance with ANSI/AWWA C651 and Health Department requirements.

D. All bacteria samples shall be no older than two weeks from the date of Application for Approval of Completed Works Certification by the engineer-of-record to the Suffolk County Department of Health Services. The contractor shall take any additional bacteria re-sample sets as required to ensure compliance with SCDHS requirements at no additional cost. The contractor shall coordinate with the engineer-of-record as required to minimize the need for additional samples.

END OF SECTION 331160