33 13 00 – Disinfection of Water

Utility Distribution

1.0 General

1.1 Summary

A. Section Includes:

1. Disinfection of potable water distribution system.

2. Testing and reporting of results.

1.2 Reference Standards

A. American Water Works Association:

1. AWWA B300 - Hypochlorites.

2. AWWA C651 - Disinfecting Water Mains.

1.3 Submittals

A. Section 01 33 00 - Submittal Procedures: Requirements for submittals.

B. Disinfection Procedure:

1. The Contractor shall submit description of procedure, including type of disinfectant and calculations indicating quantities of disinfectants required to produce specified chlorine concentration.

2. The Contractor shall submit locations of sampling points to the Engineer.

C. Product Data: The Contractor shall submit manufacturer information for proposed chemicals and treatment doses to the Engineer.

D. The Contractor shall certify that final water complies with disinfectant quality standards of the Owner.

1.4 Job Conditions

A. Environmental Requirements:

1. Testing and disinfection of water mains will not be performed if the air temperature is expected to fall below 35o F. By submission of their bid, the Contractor acknowledges this requirement and how it may impact their Work. Relief of this requirement shall only be issued in writing by the Owner, through the Engineer, at the Owner’s sole discretion.

1.5 Product Delivery, Storage, And Handling

A. The Contractor shall ensure that the transport, handling and storage of disinfection products specified herein is in a manner recommended by the respective product’s manufacturer(s) to prevent contamination and deterioration of products and to ensure safety.

B. When handling disinfection products, the Contractor shall exercise due caution.

Contractor’s employees shall wear appropriate PPE, such as but not limited to: gloves, an apron, goggles, a suitable vapor mask, etc.

1.6 Closeout Submittals

A. Section 01 77 00 - Closeout Procedures: Requirements for submittals.

B. Disinfection Report: The Contractor shall use the New Water Main Chlorine Testing form attached to the end of this Section. One form should be completed for each sample point and labeled by address or intersection. The report should also contain the following information:

1. Type and form of disinfectant used.

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

3. Test locations.

4. Name of person collecting samples.

5. Initial and 24-hour disinfectant residuals in treated water in mg/L for each outlet tested.

6. Date and time of flushing start and completion.

7. Disinfectant residual after flushing in mg/L for each outlet tested.

1.7 Quality Assurance

A. Perform Work according to AWWA C651.

2.0 Products

2.1 General

A. Disinfection chemicals shall be NSF 60 approved/certified.

B. Products in contact with potable water shall be NSF 61 approved/certified.

2.2 Disinfection Chemicals

A. Chemicals:

1. Hypochlorite: Comply with AWWA B300.

2. Liquid Chlorine: Comply with AWWA B301.

B. Powdered chlorine (e.g., calcium hypochlorite [Ca(OCl)2]) or tabular chlorine products shall not be utilized unless specifically authorized in writing, by the Owner, through the Engineer. By submission of their bid, the Contractor is acknowledging this limitation. Liquid chlorine shall be the basis of the Contractor’s bid.

3.0 Execution

3.1 Preventive and Corrective Measures During Construction

A. The Contractor shall protect the interiors of pipes, fittings, and valves from contamination.

B. The Contractor shall close openings in the pipeline with watertight end caps, plugs, or other protective device when pipe laying is stopped at the close of the day’s work or for other reasons. Rodent-proof plugs may be used when watertight plugs are not practicable and when thorough cleaning will be performed by flushing or other means.

Maintain coverings until pipes are joined.

C. The Contractor shall string pipe delivered for construction to minimize the entrance of foreign material.

D. Joints of pipe in the trench shall be completed before Work is stopped. If water accumulates in the trench, the Contractor shall keep plugs in place until the trench is free of standing water and mud that may enter the pipe.

E. Yarning or packing material shall consist of molded or tubular rubber rings, rope of treated paper, or other approved materials. Materials such as jute or hemp shall not be used. The Contractor shall handle packing material in a manner that avoids contamination.

F. No contaminated material or any material capable of supporting growth of microorganisms shall be used for sealing joints. Sealing material or gaskets shall be handled in a manner that avoids contamination. The lubricant use in the installation of sealing gaskets shall be suitable for use in potable water and meet the requirements of NSF 61 and shall not contribute odors. It shall be delivered to the job in closed containers and shall be kept clean and applied by the Contractor with dedicated, clean applicator brushes.

G. If dirt enters the pipe, the Contractor shall remove it, and the interior pipe surface swabbed with a minimum one (1) percent (1%) free chlorine disinfection solution. If, in the opinion of the Owner, the dirt remaining in the pipe will not be removed using the flushing operation, the interior of the pipe shall be cleaned using mechanical means in conjunction with the application of a minimum one (1) percent (1%) free chlorine disinfecting solution. The cleaning method used shall not force mud or debris into the interior pipe-joint spaces and shall be acceptable to the Owner.

H. If it is not possible to keep the pipe and fittings dry during installation, a scour flush at 3.0 ft/sec or greater for a minimum of three (3) pipe volumes followed by continuous-feed chlorination and bacteria testing before release is required. The

Contractor shall accomplish this, at no additional cost to the Owner.

I. If the main is flooded during construction, the Contractor shall clear it of the floodwater by draining and flushing with potable water until the main is clean. The section exposed to the floodwater shall then be filled with a chlorinated potable water that, at the end of a 24-hr holding period, will have a free chlorine residual of not less than 25 mg/L.

The chlorinated water may then be drained or flushed from the main. If chemical contamination occurs, the pipe sections exposed to the contamination should be replaced and not reused for potable water applications. After construction is completed, the main shall be disinfected using the continuous-feed method.

3.2 Testing Procedure

A. Refer to the attached “Capital Region Water - Water Main Disinfection & Commissioning

Process”.

B. The Contractor shall hydrostatically test new water main, prior to disinfection. This requirement can only be waived by the Owner, in writing.

C. For contractual purposes, free chlorine levels shall only be measured by the Owner or by their authorized representative. The Contractor shall also measure free chlorine levels, but these shall not suffice to meet the requirements herein. The Contractor shall account for this coordination requirement within their bid; no separate or additional payment shall be made.

D. Where the Contractor is not electing to truck-in water, all water used for filling, flushing, testing, etc., shall come from the Owner’s system. Water coming from the

Owner’s system shall either be obtained by the Contractor’s truck from the Water

Services Center bulk water point, at 100 Pine Drive, Harrisburg; or shall come from existing fire hydrants within the Construction Project vicinity. Where water is to come from existing fire hydrants, the Contractor shall use a Fire Hydrant Use Request, available at the following path or upon request from the Owner https://capitalregionwater.com/wp-content/uploads/2023/12/2024-01-00-Fire-

Hydrant-Use-Request.pdf The Owner will measure the Contractor’s water use during construction, and shall bill the Contractor for the water used by the Contractor during construction. The Owner, however, will reimburse the Contractor for water measured by the Owner and used by the Contractor during construction. By submission of their bid, the Contractor is acknowledging these requirements. No separate or additional payment shall be made for sourcing potable water.

E. The Contractor shall not be permitted to operate any existing valves installed on the existing water mains throughout or nearby to the Project Area. Only the Owner shall operate valves installed on water mains. If the Contractor or any of their subcontractors operate valves on water mains, the Owner will pursue damages against the Contractor. The Owner stands ready, willing, and able to operate valves on water mains, to support the activities of the Contractor, upon advanced written notification/request by the Contractor, at least 72 hours in advance.

F. New water mains shall not be directly connected to existing water mains until after full completion of disinfection and acceptance by the Owner. Only upon written authorization from the Owner shall any testing or disinfection be performed on new water mains, directly connected to and only separated from existing water main by a valve.

G. Inspect materials to be used to ensure their integrity.

H. Prevent contaminating materials from entering the water main during storage, construction, or repair and noting potential contamination at the construction site.

I. Remove, by flushing or other means, those materials that may have entered the water main or appurtenances.

https://capitalregionwater.com/wp-content/uploads/2023/12/2024-01-00-Fire-Hydrant-Use-Request.pdf https://capitalregionwater.com/wp-content/uploads/2023/12/2024-01-00-Fire-Hydrant-Use-Request.pdf

J. Prevent contamination of existing mains from cross-connection during flushing, pressure testing, and disinfection.

K. Pressure test the water main to ensure that the main meets the allowable leakage rate. Hydrostatic pressure tests should be conducted with potable water.

L. Chlorinate and adequately document the process used for disinfection:

1. Contractor will chlorinate the pipe and test free chlorine residual levels (must be between 25 and 50 mg/L):

a) Ensure that all valves, hydrants, blowoffs, and other pipeline appurtenances are thoroughly operated so that they maintain sufficient contact with the chlorine solution during the disinfection process.

2. 24-hour hold period.

M. Contractor will test for free chlorine residual. All sampling points must have a minimum residual of 10 mg/L. If test results are acceptable, Contractor will flush the chlorinated water from the main in accordance with AWWA C655. Chlorine residual must be between 1.00 and 3.00 mg/L. Contractor shall verify acceptable system levels at the end of flushing.

N. Determine the bacteriological quality of water samples collected from the pipe by laboratory test after disinfection. Refer to Paragraph 3.8. Both sets of bacteriological and water quality samples are to be taken by a third-party certified laboratory, at no additional cost to the Owner. Owner and Engineer must approve both sets of test results before the water main can be put into service.

O. Final connection of the newly disinfected water main to the active distribution system without sacrificing sanitary practices and conditions.

3.3 Methods of Chlorination

A. General: All water mains installed as part of this Work shall be disinfected by chlorination by the Contractor and shall be completed in accordance with AWWA C651.

B. The Contractor shall flush the source of potable water used for disinfection and pressure testing prior to its use to ensure that contaminants or debris are not introduced into the new pipe. The Contractor shall provide adequate drainage during flushing. Drainage should take place away from the construction area. During the contact period, the valve isolating the new water main from the existing water system

(if applicable) shall be tagged to prevent unintentional release of the elevated chlorine residual water into the existing water system.

C. Tablet Method (when authorized by the Owner, in writing):

1. The tablet method consists of placing calcium hypochlorite tablets or granules in the water main as the main is being installed and then filling the main with potable water to create a chlorine solution with a minimum dose of 25 mg/L but shall not exceed 50 mg/L when installation is completed. This method may only be used if pre-approved by the Owner in writing and if the Contractor keeps the pipes and appurtenances clean and dry during construction. Failure to meet the required minimum residual after a 24-hour hold or failure to obtain satisfactory bacteriological sample results after application of the tablet method will require the

Contractor to switch to another approved method.

2. Placing of calcium hypochlorite tablets: During construction, 5-gram calcium hypochlorite tablets shall be placed in the upstream end of each section of pipe to be disinfected, at the upstream end of each branch main, and at 500-ft. intervals.

Also, at least one tablet shall be placed in each hydrant, hydrant branch, and other appurtenances. The tablets shall be attached by an adhesive meeting the requirements of NSF 61 and used in accordance with the manufacturer’s instructions. There shall be adhesive only on the broadside of the tablet attached to the surface of the pipe. Attach tablets inside and at the top of the water main, with approximately equal number of tablets at each end of a given pipe length. If the tablets are attached prior to the pipe section being placed in the trench, their position shall be marked to indicate that the pipe has been installed with the tablets on top.

Number Of 5 Gram Calcium Hypochlorite Tablets Required For Dose Of

25 mg/L*

LENGTH OF PIPE SECTION, FT.

13 OR

LESS

18 20 40

PIPE DIAMETER NUMBER OF 5-g CALCIUM HYPOCHLORITE

TABLETS INCHES

4 1 1 1 1

6 1 1 1 2

8 1 2 2 4

10 2 3 3 5

12 3 4 4 7

*Based on 3.25-g available chlorine per tablet; any portion of tablet rounded to the next highest integer.

3. Placing of calcium hypochlorite granules: During construction the Contractor shall place granules in pipe sections at the upstream end of the first section of pipe, at the upstream end of each branch main, and at 500 feet intervals.

Quantity of granules as specified in the table below.

Ounces Of Calcium Hypochlorite Granules To Be Placed At Beginning Of

Main And At Each 500 Foot Interval

Pipe Diameter (in.)

Calcium Hypochlorite Granules

oz. (g)

4 1.7 48

6 3.8 108

8 6.7 190

10 10.5 298

12 15.1 428

4. Filling and Contact: When installation is completed, the Contractor shall fill the main with water at a rate to ensure that the water within the main will flow at a velocity no greater than 1ft/sec. The fill rate must be carefully controlled to ensure tablets do not come loose from pipe or to prevent granules from being washed downstream before being dissolved. The Contractor shall take precautions to ensure that air pockets are eliminated. This water shall remain in the pipe for a minimum of 24 hours. If the water temperature is less than 41oF, the water shall remain in the pipe for at least 48 hours. A detectable free chlorine residual of not less than 10 mg/L shall be taken at each sampling point after the required time period. The results must be reported.

3.4 Continuous-Feed Method:

A. Preliminary flushing: Before the main is chlorinated, the Contractor shall fill it to eliminate air pockets and flushed to remove particulates. The flushing velocity in the main shall not be less than 3.0 ft/sec. The table below shows the rates of flow required to produce a velocity of 3.0 ft/s.

Required Flow And Openings to Flush Pipelines at 3.0 ft/s

Pipe

Diameter

Flow

Required to Produce

3.0 ft/s

Velocity in

Main

Size of Tap Used, in.

Number of Hydrant

Outlets 1 1-1/2 2

in. gpm Number of Taps Required on Pipe 2-1/2 in. 4-1/2 in.

4 120 1 - - 1 1

6 260 - 1 - 1 1

8 470 - 2 - 1 1

10 730 - 3 2 1 1

12 1060 - - 3 2 1

* With a 40-psi pressure in the main with the hydrant flowing to atmosphere.

B. Procedure For Chlorinating the Main:

1. Water supplied from the existing distribution system shall flow at a constant, measured rate into the newly installed water main. The Contractor shall complete hydrostatic testing of the main prior to disinfection.

2. At a point not more than 10 feet downstream from the beginning of the new main, water entering the new main shall receive a dose of chlorine fed at a constant rate such that the water will have not less than 25 mg/L free chlorine. To ensure that this concentration is provided, the Contractor shall ensure that the free chlorine concentration is measured at regular intervals in accordance with the procedures described in the current edition of Standard Methods for the Examination of Water and Wastewater or AWWA M12 or using appropriate chlorine test kits. The table below gives the amount of chlorine required for each 100 ft. of pipe. Solutions with a minimum one (1) percent (1%) chlorine concentration may be prepared with sodium hypochlorite or calcium hypochlorite. The latter solution requires one (1)

lb. of calcium hypochlorite in eight (8) gallons of water.

3. Chlorine application shall not cease until the entire main is filled with heavily chlorinated water at a minimum dose of 25 mg/L. The chlorinated water shall be retained in the main for at least 24 hours, during which time the Contractor shall operate valves and hydrants in the treated section to ensure disinfection of the appurtenances. At the end of this 24-hour period, the treated water in all portions of the main shall have a residual of not less than 10 mg/L of free chlorine, as measured by the Owner or their authorized representative.

4. The Contractor shall introduce the hypochlorite solution to the water main with a gasoline or electrically-powered chemical feed pump designed for feeding chlorine solutions. Feed lines shall be made of material capable of withstanding the corrosion caused by the concentrated chlorine solutions and the maximum pressures created that may be created by the pumps. The Contractor shall check all connections for tightness before the solution is applied to the water main. For smaller applications, the solution may be prepared in a barrel, and then pumped into the main with a hand pump, such as a hydraulic test pump. Apply at a dosage rate such that the chlorine concentration in the water in the pipe is a minimum of

25 mg/L free chlorine. The following table gives the amount of calcium hypochlorite and the quantity of one (1) percent (1%) hypochlorite solution required to produce a 25 mg/L chlorine concentrate in 100 ft. of pipe:

CALCIUM HYPOCHLORITE AND CHLORINE SOLUTION REQUIRED

TO PRODUCE 25 MG/L CONCENTRATION IN 100 FEET OF PIPE

Amount of Calcium

Hypochlorite

1% Chlorine

Solution

Gallons Pipe Size

Inches

Contents in

Cu.Ft.

100-ft. Lbs. Section

Gallons Ounces Pounds

6 19.65 1,227 147 3/4 0.046 0.36

8 34.90 2,178 261 1-3/8 0.083 0.65

10 54.28 3,388 406 2-1/8 0.131 1.02

12 78.48 4,899 587 3-0 0.185 1.44

FEET OF PIPE IN WHICH 1 OUNCE OF CALCIUM

HYPOCHLORITE WILL PRODUCE 25 MG/L AVAILABLE CHLORINE

Pipe Size

(in.)

6 8 10 12

Feet of Pipe 144 79 51 36

5. The Contractor shall apply the chlorinating agent at the high end of the pipeline section being chlorinated, and through a corporation stop inserted in the top of the new pipe. If the water for the preparation of the chlorine solution is supplied from a tap on the existing pipeline, the Contractor shall ensure that there is a physical break between the injector supply and the injector or pump.

6. To prevent any introduction of strong chlorinated water from entering the drinking water distribution system, only the Owner shall manipulate distribution system valves during construction, and new water mains shall not be directly connected to the existing water distribution system, even if isolated by a valve (except with written pre-authorization from the Owner).

C. Slug Method (when authorized by the Owner in writing):

1. The slug method consists of the Contractor placing calcium hypochlorite granules in the water main during construction, completely filling the water main with water to eliminate air pockets, flushing the main to remove particulates, and slowly flowing through the main a slug of water dosed with chlorine to a concentration of

100 mg/L. The slow rate of flow ensures that all parts of the main and its appurtenances will be exposed to the highly chlorinated water for a period of not less than 3 hours. (This method shall not be employed without written authorization from the Owner.)

2. Placing calcium hypochlorite granules: Refer to Paragraph 3.3.C.3.

3. Preliminary flushing: Refer to Paragraph 3.3.D.1.

4. Chlorinating the main: Refer to Paragraph 3.3.D.2:

a. At a point not more than 10 ft. downstream of the beginning of the new water main, water entering the new main shall receive a dose of chlorine fed at a constant such that the water will have not less than 100 mg/L free chlorine.

The chlorine shall be measured at regular intervals. The chlorine shall be applied continuously and for a sufficient period to develop a solid column, or slug, of chlorinated water that will, as it moves through the water main, expose all interior surfaces to a concentration of approximately 100 mg/L for no less than 3 hours.

b. The free chlorine residual shall be measured in the slug as it moves through the main. If at any time it drops below 50 mg/L, the flow shall be stopped, the chlorination equipment shall be relocated at the head of the slug, and as flow resumes, the chlorine shall be applied to restore the free chlorine in the slug to not less than 100 mg/L.

c. As the chlorinated water flows past fittings and valves, related valves and hydrants shall be operated so as to disinfect appurtenances and pipe branches.

3.4 Final Flushing

A. After the applicable retention period, heavily chlorinated water should not remain in prolonged contact with pipe. In order to prevent damage to the pipe lining or corrosion damage to the pipe itself, the Contractor shall flush heavily chlorinated water from the main, fittings, valves, and branches, or taps in the main installed at the Contractors expense, until chlorine measurements show that the concentration in the water leaving the main is no higher than that generally prevailing in the existing distribution system or that is acceptable for domestic use (if no existing distribution system).

B. The environment to which the chlorinated water is to be discharged shall be inspected.

If there is any possibility that the chlorinated discharge will cause damage to the environment, the Contractor shall apply a neutralizing chemical to the water to be wasted to thoroughly neutralize the residual chlorine. When necessary, federal, state, or local regulatory agencies should be contacted to determine special provisions for the disposal of heavily chlorinated water.

C. All Work involving chlorinated water discharges to the surface, such as but not limited to flushing of water mains and hydrants, water system disinfection, and hydrostatic testing shall be dechlorinated in accordance with PADEP regulations pertaining to the

Planned and Unplanned Discharges of Chlorinated Waters to Surface Waters. Refer to

Section 01 41 26 – Permit Requirements.

3.5 Final Connection to Existing Mains

A. Water mains must be completely installed, flushed, disinfected, and satisfactory bacteriological sample results received and approved by the Owner in writing prior to permanent connections being made to the active distribution system. The Contractor shall follow sanitary construction practices during installation of the final connection so that there is no contamination of the new or existing water main with foreign material or groundwater:

1. New pipe, fittings, and valves required for the connection shall be spray-disinfected or swabbed with a minimum one (1) percent (1%) solution of chlorine just prior to being installed, if the total length of the connection from the end of a new main to the existing main is equal to or less than 20 feet.

2. The pipe required for connection must be set up aboveground and disinfected with bacteriological samples taken if the total length of the connection from the end of a new main to the existing main is greater than 20 feet. After satisfactory bacteriological sample results have been received for the predisinfected pipe, the pipe can be used in connecting the new main to the active distribution system.

Between the time the satisfactory bacteriological sample results are received and the time that the connection piping is installed, the ends of the piping must be sealed with plastic wraps, watertight plugs, or caps.

3.6 Disinfection Procedures When Cutting into Existing Mains

A. Disinfection procedures when cutting into existing mains shall be completed in accordance with AWWA C651.

B. Controlled pipe connection with depressurization after shutdown:

1. In this situation, after the repair site has been exposed and secured from trench soil/water contamination, the water main is depressurized by a shutdown to complete the repair. The repair site should be cleaned and disinfected by spraying or swabbing with a minimum 1 percent chlorine solution. The water main is then returned to service with flushing to scour the pipe and obtain three (3) volumes of water turnover, making sure that the flushed water is visually clear. It is advisable to check for atypical system chlorine residual and, if it is not found, to continue flushing until residuals are restored to levels maintained in the distribution system by the Owner.

C. When the existing pipe has to be opened and the interior surfaces of the water system exposed to the environment, the following additional procedures need to be followed:

1. The existing pipe should be inspected and cleaned, utilizing flushing water into the trench where possible until the flush water runs visually clear.

2. The repair site should be accessible, and the trench adequately dewatered so that the repair site can be cleaned and disinfected by spraying or swabbing with a minimum one (1) percent (1%) chlorine solution.

3. Additionally, any accessible upstream and downstream interior of the existing pipe should be disinfected by swabbing or spraying with a minimum of one (1) percent

(1%) chlorine solution.

4. The water main may then be returned to service after flushing to scour the pipe and obtain three (3) volumes of water turnover. The flushed water should run visually clear, have a measurable chlorine residual if the system operates with a residual, and be checked with bacteriological testing. The pipeline may be returned to service before obtaining bacteriological testing.

D. If valve and hydrant locations permit, the Contractor shall flush toward the Work location from both directions. The Contractor shall start flushing as soon as the connections are completed and shall be continued until discolored water is eliminated.

E. Bacteriological samples following procedures stated in paragraph 3.8 shall be taken after connections are completed. If positive bacteriological samples are not recorded, then corrective actions shall be taken by the Contractor and coordinated with the

Owner and Engineer. 24-hour sampling shall be continued until two (2) consecutive negative samples are recorded and reviewed by and approved (in writing) by the

Owner.

3.7 Temporary Service Lines

A. Temporary water service lines to customers during main repair activities shall be disinfected by the Contractor prior to use. Materials shall meet the NSF 61 certification for potable water use. The Contractor shall accomplish disinfection by the procedures in Paragraph 3.3 followed by scour flushing at 3.0 ft/sec or greater for a minimum of three (3) pipe volumes, or until the water runs visually clear and preferably a measurable chlorine residual is restored.

3.8 Sampling

A. The Contractor shall ensure that at least one (1) set of samples is collected from every

1,200 ft. of the new water main, plus one (1) set from each end of the line, including the injection site, and at least one (1) set from each branch, greater than one (1) pipe length. The Contractor shall have samples tested for bacteriological (chemical and physical) quality in accordance with Standards Methods for the Examination of Water and Wastewater; and the samples shall show the absence of total coliform bacteria and E.coli. , the presence of a chlorine residual, Turbidity (must be < 1 NTU), pH (must be between 6.5 and 8.5), temperature, and a standard heterotrophic plate count (HPC) test (must be < 500 CFU/mL).

B. If trench water has entered the new main during construction or if excessive quantities of dirt or debris have entered the new main, the Contractor shall have bacteriological samples taken at intervals of approximately 200 ft., and/or at locations coordinated with the Owner and Engineer. Samples shall be taken of water that has stood in the new main for at least 16 hours after final flushing has been completed.

C. The Contractor shall ensure that samples for bacteriological analysis are collected in sterile bottles treated with sodium thiosulfate, as required by Section 9060 – Samples of Standard Methods for the Examination of Water and Wastewater. No hose or fire hydrant shall be used in the collection of samples. For pipe repairs, if no other sampling port is available, well-flushed fire hydrants may be used. There should be no water in the trench up to the connection for sampling. The sampling pipe must be cleaned and disinfected and flushed prior to sampling. A corporation stop may be installed in the main at the Contractor’s expense to facilitate sampling with a copper-tube gooseneck assembly. After samples have been collected, the Contractor shall remove the gooseneck assembly and the corporation stop closed and plugged. Sample corporation cocks shall be placed in the 2 o’clock or 10 o’clock position.

D. If sample results from the lab indicate a measured HPC greater than 500 colony-forming units (CFU) per mL, the Contractor should resume flushing (and redisinfection if required by Owner and Engineer) and another coliform and HPC set of samples should be taken until no coliforms are present and the HPS is less than 500 CFU/mL, as verified (in writing) to the satisfaction of the Owner.

E. The record of compliance shall be the bacteriological test results certifying that the water sampled from the new water main is free of coliform bacteria contamination and is equal to or better than the bacteriologic water quality in the distribution system, as verified (in writing) to the satisfaction of the Owner.

F. If the water main is not promptly put into service, the Owner and Engineer will evaluate to determine if the water quality may have been impacted and if additional testing and further action, such as but not limited to flushing and redisinfection, is warranted at no additional cost to the Owner.

G. The Contractor shall include costs in their bid for, but not exclusively, the following:

the disinfection, including laboratory analysis, of the water main; coordination with certified testing laboratory on testing for the bacteria quality.

H. The Contractor shall coordinate with Owner should a Boil Water Advisory need to be issued following connection to existing water mains. By submission of their bid, the

Contractor acknowledges the seriousness of this Work and also the seriousness regarding a Boil Water Advisory – should the Owner have to issue one, due to the actions of the Contractor.

I. The Owner is the sole entity that can confirm the suitability of third-party, certified, laboratory test results, indicating that the new water main is safe for use. The

Contractor shall not connect any new main to the existing distribution system, or otherwise put new water main into use, without first having written authorization from the Owner.

3.9 Redisinfection

A. If the initial disinfection fails to produce satisfactory bacteriological results or if other water quality is affected, the new main may be reflushed and shall be resampled. If check samples also fail to produce acceptable results, the Contractor shall rechlorinate the main by the continuous-feed method until satisfactory results are obtained, that being two consecutive sets of acceptable samples taken 24 hours apart.

END OF SECTION

33 13 00-B CRW Water Main

Disinfection Process Cover Sheet

2027 Sewer System Improvements Project

CRW Water Main Disinfection & Commissioning Process

No. of Pages: 1

CAPITAL REGION WATER

Water Main DisinfecƟon & Commissioning Process

This flowchart is intended to provide a general process overview and idenƟfy responsible party in bold.

DisinfecƟon must follow AWWA C651 – DisinfecƟng Water Mains (latest ediƟon) and related AWWA standards.

CRW will provide the contractor with SpecificaƟon 33 13 00 – DisinfecƟon of Water UƟlity DistribuƟon for complete requirements.

Last revised 9/13/2024

•At least one set of samples shall be collected from every 1,200 linear feet of new water main, plus one set from the end of the line and at least one set from each branch, greater than one pipe length.

•CONTRACTOR shall submit drawings showing proposed sampling points. CRW must approve before CONTRACTOR schedules testing.

•Before scheduling any testing, CONTRACTOR shall provide minimum 1-week notice via email to CRW and ENGINEER. Use of either hypochlorite or liquid chlorine is permissible.

•CONTRACTOR will superchlorinate the pipe and test free chlorine residual levels (must be between 25 and 200 mg/L). All chlorine readings must be coordinated through the ENGINEER/RPR, who will verify CRW Water Quality Administrator WQA is available for testing.

•CRW (WQA) will test free chlorine levels on the scheduled day/time.

•Let pipe sit for 24 hours.

•CONTRACTOR and CRW WQA will test free chlorine residual. CRW test results govern. All sampling points must have a minimum of 10 mg/L to continue.

•If test results are acceptable, CONTRACTOR will flush pipe to match existing free chlorine residual in the system (must be between 1.00 and 3.00 mg/L).

•CRW WQA will verify acceptable system levels at the end of flushing.

•Let pipe sit for 16 hours.

•First set of samples to be taken by a THIRD PARTY CERTIFIED LAB. Two (2) sets of passing samples, 24-hours apart, are required to continue.

•The following parameters will be tested by the lab: a) pH must be between 6.5 and 8.5 b) Turbidity must be < 1 NTU c) Chlorine must be between 0.2 and 4.4 mg/L

d) Test for absence of coliform organism and a standard heterotrohphic plate count (HPC) e) Temperature will be recorded.

•Let pipe sit for 24 hours.

•Second set of samples will be collected by THIRD PARTY CERTIFIED LAB. Collect and repeat sampling for all parameters listed in Step 4.

•CONTRACTOR will send one email containing both sets of lab results to CRW WQA and ENGINEER/RPR.

•CRW WQA must approve both sets of test results via email to project team before water main can be turned in to service.

•If any samples fail, CONTRACTOR shall restart the process at Step 2.