ADDENDUM NO. 2
May 20, 2014
CENEX WATER TOWER REHABILITATION
CITY OF WASHBURN, NORTH DAKOTA
BID DATE:
May 22, 2014
BID DEADLINE:
BID OPENING:
2:00 PM
2:15 PM
LOCATION:
Office of the City Auditor
907 Main Ave., PO Box 467
Washburn, ND 58577
This document was
originally issued and sealed by
Jasper Klein, PE,
Registration Number 7875
on
May 20, 2014
and the original document
is stored at the office of
Advanced Engineering &
Environmental Services, Inc.
This Addendum forms part of the Contract Documents and modifies the original Bidding Documents
as noted below. Acknowledge receipt of this Addendum on the exterior of the envelope containing the
bid and in the space provided on the Bid Form. Failure to do so may subject the Bidder to
disqualification.
Bidding information and Addenda are available at AE2S.com/Project Bidding.
This Addendum consists of one (1) page and two (2) attachments.
CHANGES TO SPECIFICATIONS
1.
Section 00431: MBE/WBE SUBCONTRACTOR SOLICITATION INFORMATION
a. ADD the attached Wage Decision Number ND15 to the end of section.
2.
Section 02675: CLEANING AND DISINFECTION OF WATER SYSTEM
a. ADD the attached section.
3.
Section 013220: ELEVATED WATER STORAGE TANK RECONDITIONING
a. 1.03.B.12 ADD: Turn-down elbow shall be brought 12-24 inches above splash pad.
End of Addendum
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DIVISION 2 - SITE WORK
SECTION 02675 CLEANING AND DISINFECTION OF WATER SYSTEM
PART 1
1.01
1.02
SUMMARY
A.
Section includes:
1.
Cleaning and disinfection of potable water system.
2.
Testing and reporting results.
B.
Related Sections included, but are not limited to:
1.
Section 01300 - Submittals.
2.
Section 01400 - Quality Control.
3.
Section 01700 - Contract Closeout.
4.
Section 02667 - Site Piping.
5.
Section 02704 - Pipeline Pressure and Leakage Testing.
6.
Section 03969 – Water Tightness Testing
REFERENCES
A.
1.03
1.04
GENERAL
Reference Standards include:
1.
AWWA B300 - Standard for Hypochlorites.
2.
AWWA B301 - Standard for Liquid Chlorine.
3.
AWWA C651 - Standards for Disinfecting Water Mains.
4.
AWWA C652 – Standards for Disinfection of Water Storage Facilities
5.
AWWA C653 – Standards for Disinfection of Water Treatment Plants.
6.
Federal Specifications BB-C-12a, O-C-114a, and O-C-602b.
DEFINITIONS
A.
Disinfectant Residual means the quantity of disinfectant in the treated water.
B.
PPM means parts per million.
SUBMITTALS FOR REVIEW
A.
Section 01300 - Submittals: Procedures for submittals.
B.
Test Reports: Indicate results comparative to specified requirements.
C.
Section 01400: BAC-T Test Results. (Testing costs shall be incidental)
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D.
1.05
1.06
Disinfection Plan: Not less than 7 days prior to starting any disinfection work, the
Contractor shall submit to the Engineer a detailed cleaning and disinfection plan.
The plan shall cover the method and procedure proposed, to include
coordination, the time and sequence of operations, the limits of the pipeline to be
cleaned and disinfected, the location of temporary bulkheads, equipment to be
used, the manner of filling and flushing of lines, the neutralization and disposal of
wasted water, and all other methods and procedures to be followed in performing
the required cleaning and disinfection Work.
PROJECT RECORD DOCUMENTS
A.
Submit under provisions of Section 01300 - Submittals and Section 01700 Contract Closeout.
B.
Disinfection report:
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 final 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.
C.
Bacteriological report:
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 final disinfectant residuals in ppm for each outlet tested.
6.
Coliform bacteria test results for each outlet tested.
QUALITY ASSURANCE
A.
Perform Work in accordance with AWWA C651 for disinfecting of water lines,
AWWA C652 for disinfection of water storage facilities, and AWWA C653 for
disinfection of water treatment plants.
B.
Regulatory Agency Requirements: Comply with the North Dakota Department of
Health requirements.
C.
Temporary bulkheads shall be provided during cleaning and disinfection so that
the flushing and disinfection work is not applied to existing water lines or to any
portion of new lines installed under this Contract that has been put into service.
D.
The cleaning and disinfection work shall be conducted prior to connection to the
existing water lines or to any portion that has been put into service of new lines
installed under this Contract. Unless otherwise approved, hydrostatic testing
shall be completed prior to final cleaning and disinfection.
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E.
1.07
DELIVERY, STORAGE, AND HANDLING
A.
Protect against damage and contamination.
B.
Maintain caution labels on hazardous materials.
C.
Maintain storage room dry and with temperatures as uniform as possible
between 60 and 80 degrees F.
D.
Provide necessary signs, barricades, and notices to prevent any person from
accidentally consuming water or disturbing system being treated.
PART 2
2.01
PRODUCTS
DISINFECTION CHEMICALS
A.
AWWA B300, Hypochlorite: Shall conform to Federal Specification O-C-114a,
Type II, Grade B, or Federal Specification O-C-602b.
B.
AWWA B301, Liquid Chlorine:
120a.
PART 3
3.01
Testing Laboratory:
1.
Bacteriological samples need to be analyzed by a ND state certified lab.
2.
Contractor shall obtain sampling bottles from an approved laboratory and
perform sampling per project requirements and sampling protocol.
3.
Contractor shall coordinate sampling and testing schedule with the
laboratory. Contractor shall pay all testing fees and lab costs.
Shall conform to Federal Specification BB-C-
EXECUTION
DISINFECTION PLAN
A.
Submit a detailed cleaning and disinfection plan to the Engineer, not less than 7
days prior to starting any disinfection work.
B.
The Plan shall cover the method and procedure proposed, to include coordination, the time and sequence of operations, the limits of the pipeline to be
cleaned and disinfected, the location of temporary bulkheads, equipment to be
used, the manner of filling and flushing the lines, the neutralization and disposal
of wastewater, and all other procedures and methods to be followed in
performing the required cleaning and disinfection Work.
C.
The Contractor shall provide all necessary piping connections, temporary valves,
sampling taps, pumps, disinfectant, neutralization agents, chlorine residual test
apparatus, and all other items of equipment or facilities required to complete the
disinfection Work.
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3.02
3.03
3.04
PREPARATION
A.
Verify that piping system has been cleaned, inspected, pressure tested, and
flushed. The line shall be cleaned by flushing the line at the maximum velocity.
B.
Perform water main and associated appurtenances disinfection activity before
returning permanent water service to said Work area. Coordinate with Engineer
and Owner.
DISINFECTION OF WATER SYSTEMS
A.
Provide and attach required tools, equipment, and materials to perform the Work
of this Section. Disinfectant material shall be introduced into the water system
through a corporation cock installed in the top of the pipe.
B.
Inject treatment disinfectant into piping system to produce at least 50 ppm
retained for 24 hours or 200 ppm retained for 3 hours.
C.
As chlorinated water flows past fittings and valves, related valves and hydrants
shall be operated so as to disinfect appurtenances and pipe branches.
D.
If disinfectant residual is less than the acceptable limit, repeat system treatment.
E.
Flush, circulate, and clean until the chlorine residual is lowered to approximately
1.0 ppm; use system water supply.
F.
Upon making service lead connections, flush or inform property owner or tenant
to flush water through associated service system for a period sufficient to fully
turn-over the water service system. Provide bacteriological tests.
G.
Any sections of water main and service leads that cannot be chlorinated in the
fashion stated in this section and the final service lead tie-in points shall be
swabbed with a chlorine solution prior to installation.
H.
Chlorination of water tank shall meet AWWA C652 Method 2 or 3. See Section
3.04 of this specification.
I.
Properly dispose of heavily chlorinated water supply in an environmentally
acceptable manner.
DISINFECTION OF WATER TANKS
A. Chlorination of water tank shall meet AWWA C652 Method 2 or 3.
B. AWWA C652 Method 2
1.
A solution of at least 200-mg/L available chlorine shall be applied directly
to the surfaces of parts of the storage facility that would be in contact with
water when the storage facility is full to the overflow elevation.
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2.
3.
4.
The chlorine solution may be applied with suitable brushes or spray
equipment. The solution shall thoroughly coat surfaces to be treated,
including the inlet and outlet piping, and shall be applied to any separate
drain piping such that it will have available chlorine of not less than 10
mg/l when filled with water. Overflow piping need not be disinfected.
The disinfected surfaces shall remain in contact with the strong chlorine
solution for at least 30 min, after which potable water shall be admitted,
the drain piping purged of the 10-mg/l chlorinated water, and the storage
facility then filled to its overflow level.
Following this procedure and subject to satisfactory bacteriological
testing, appropriate chlorine residual, and acceptable aesthetic water, the
water may be delivered to the distribution system.
C. AWWA C652 Method 3
1.
2.
3.
4.
Water and chlorine shall be added to the storage facility in amounts such
that the solution will initially contain at least 50 mg/l available chlorine and
will fill approximately 5 percent of the total storage volume.
This solution shall be held in the storage facility for a period of not less
than 6 hr. The storage facility shall then be filled to the overflow level by
flowing potable water into the highly chlorinated water. It shall be held
full for a period of not less than 24 hr. Highly chlorinated water shall then
be purged from the drain piping.
Following this procedure and subject to satisfactory bacteriological
testing, appropriate chlorine residual, and acceptable aesthetic water, the
water may be delivered to the distribution system.
Chlorine shall be added to the storage facility by the method described in
3.04.D. of this specification. The actual volume of the 50 mg/l chlorine
solution shall be such that, after the solution is mixed with filling water and
the storage facility is held for 24 hr, there will be a free-chlorine residual of
not less than 2 mg/l.
D. Adding Chlorine shall follow the procedures below.
1.
Liquid-chlorine use. Liquid chlorine shall be introduced into the water
filling the storage facility in such a way as to give a uniform chlorine
concentration during the entire filling operation. Portable chlorination
equipment shall be carefully operated and shall include a liquid-chlorine
cylinder, gas-flow chlorinate, chlorine ejector, safety equipment, and an
appropriate solution tube to inject the high-concentration chlorine solution
into the filling water. The solution tube shall be inserted through an
appropriate valve located on the inlet pipe and near the storage facility
such that the chlorine solution will mix readily with the influent water.
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2.
Sodium hypochlorite use. Sodium hypochlorite shall be added to the
water entering the storage facility by means of a chemical feed pump or
shall be applied by hand-pouring into the storage facility and allowing the
influent water to provide the desired mixing.
a.
b.
3.
3.05
When a chemical-feed pump is used, the concentrated chlorine
solution shall be pumped through an appropriate solution tube so
as to inject the high-concentration chlorine solution at a rate that
will give a uniform chlorine concentration in the filling water. The
solution tube shall be inserted through an appropriate valve
located on the inlet pipe and near the storage facility, or through
an appropriate valve located on the storage facility such that the
chlorine solution will mix readily with the filling water.
When sodium hypochlorite is poured into the storage facility, the
filling of the storage facility shall begin immediately thereafter or
as soon as any removed manhole covers can be closed. Sodium
hypochlorite may be pored through the cleanout or inspection
manhole in the lower course or level of the storage facility, in the
riser pipe of an elevated thank, or through the roof manhole.
Sodium hypochlorite shall be poured into the water in the storage
facility when the water is not more than 3 ft in depth, nor less than
1 ft in depth or a close thereto as manhole locations permit.
Calcium hypochlorite use. Calcium hypochlorite granules or tablets
broken or crushed to sizes not larger than 0.25 in. maximum dimension
may be poured or carried into the storage facility through the cleanout or
inspection manhole in the lower course or level of the storage facility, into
the riser pipe or an elevated tank, or through the roof manhole. The
granules or table particles shall be placed in the storage facility before
flowing water into it. The granules or tables shall be located so that the
influent water will circulate through the calcium hypochlorite, dissolving it
during the filling operation. The calcium hypochlorite shall be placed only
on dry surfaces unless adequate precautions are taken to provide
ventilation or protective breathing equipment.
FIELD QUALITY CONTROL
A.
Section 01400 - Quality Control: Field inspection and testing.
B.
Samples for bacteriological analysis shall be collected in sterile bottles obtained
from an acceptable laboratory.
C.
Two or more successive test samples indicating bacteriological satisfactory water
shall be obtained before any system is placed into operation.
D.
If initial disinfection fails to produce satisfactory bacteriological results, the new
main may be reflushed and shall be resampled. If check samples also fail to
produce acceptable results, the main shall be rechlorinated until satisfactory
results are obtained.
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E.
All testing costs shall be paid for by Contractor.
F.
Water mains and appurtenances must be completely installed, flushed,
disinfected, and satisfactory bacteriological sample results received prior to
permanent connections being made to the active distribution system. Sanitary
construction practices must be followed during installation of the final connection,
so that there is no contamination of the new or existing water main.
END OF SECTION
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