Exh 3AAGENDA ITEM #3A
JULY 28, 2003
CITY OF ATLANTIC BEACH
CITY COMMISSION MEETING
STAFF REPORT
AGENDA ITEM: Corrosion Control in Atlantic Beach Water System
SUBMITTED BY: Donna Kaluzniak, CEP, Utility Director
DATE: July 21, 2003
BACKGROUND: At the July 14, 2003 Commission Meeting a concerned was raised about
the copper level noted in the water quality report and a statement made that the City's water was
corrosive due to the treatment process resulting in the addition of oxygen and incomplete
reduction of hydrogen sulfide causing the water to become acidic, leading to corrosion of
residential plumbing. During a meeting with the concerned citizen and City staff addition of
polyphosphate to the water system was proposed as a solution.
Staff cazefixlly reviewed data on the finished water (after treatment) from the Atlantic Beach
Water System. The data demonstrates that the water is not coaosive:
^ Conner levels: As noted in the water quality report, DEP's "action level" for copper,
which is the level that indicates a corrosivity problem and would require the City to take
action is 1.3 parts per million (ppm). The level of copper in the Atlantic Beach system
(from samples taken at residential locations) is 0.053 ppm, well below the Action level,
indicating no problem with corrosivity. None of the homes tested exceeded the action
level.
^ The Lang_elier Index (L.L1 is the most common index used to indicate'the corrosiveness of
water. A negative L.I. indicates corrosive water, and a positive L.I. indicates the opposite
(scale forming) water. Ideally the L.I. should. be between -0.5 and.+.0.5, which indicates
a balanced water. Atlantic Beach's L.I. is +0.05, indicating a balanced system on the
side of scale forming.
^ Hazdness: Hazdness is associated with the concentration of calcium and magnesium in the
water. Hazd water is not corrosive, but can be the opposite (scale forming).
Atlantic Beach has very hard water, equivalent to 14 grains per gallon.
^ Alkalinity: Corrosivity occurs with waters that are low in alkalinity (40 ppm or less).
Alkalinity is the buffering capability of water, which means the water can resist a change in
pH. Atlantic Beach water has an alkalinity level of about 140 ppm, well above the level
associated with corrosive waters.
^ pH: Corrosive waters are typically on the acid end. of the pH scale. The pH scale ranges
from 0.0 to 14.0 Standard Units (S.U.), with 7.0 as neutral. Values under 7.0 aze on the
acid end of the scale, and values over 7.0 aze alkaline. The pH of the water in Atlantic
Beach averages about 7.4 and ranges from 7.1 to 7.6 (alkaline), both at the treatment
plant and in the distribution system.
AGENDA ITEM #3A
JiJLY 28; 2003
All of the data indicates that there is no corrosion problem with the water. On the contrary, there
may be a tendency for scale formation (a buildup of minerals onpiping or equipment, especially
with high temperature waters such as in water heaters}. Reducing hardness and scale formation
was discussed as an aesthetic improvement in the Water Master Plan, which recommended low
pressure reverse osmosis (LPRO) as the best solution, at a cost of $4.25 million.
The Water Master Plan included an evaluation all regulatory aspects of the City's water, including
corrosivity tesulting in copper problems and found. no problems with the City water causing
corrosion of piping in Atlantic Beach,
There are several potential causes of household plumbing corrosion, including:.
^ Imnroner electrical grounding (grounding of electric circuits to water pipes, which is no
longer allowed).
^ Stray electrical currents from. other utilities, such as cable or phone companies, who may
erroneously use water pipe for grounding.
^ Installation errors, such as inadequate de-burring of cut tubing, use of excessive or
improper flux material, overheating joints, and failure to flush the pipe properly after
installation can cause pitting, internal weaz and. tubing failure, especially neaz fittings.
^ Dissimilar metals joined improperly. When two different metals such as steel and brass aze
in contact with a solution which will conduct electricity, a galvanic cell is established. One
of the metals will corrode in proportion to the electricity generated. If plumbing is installed
using different metals (copper, steel, brass, zinc, and various alloys) corrosion will occur.
This happens most often when copper lines touch steel wall studs, steel pipe hangers,
shielded "tech-cable" or when steel pumps or valves aze attached directly to copper pipe:
^ Galvanic corrosion of steel pine embedded in concrete, especially where plumbing comes
up through the slab ff it is not properly sleeved.
^ Undersized pinin¢ can cause corrosion due to excess velocity in the pipe. This can cause
cavitation in the piping or impingement attack. Based on information from the American.
Waterworks Research Foundation, velocities in copper piping should be limited to 5 feet
per second (fps) for cold water piping. and 4 fps for hot water piping. To reduce velocity,
increase the pipe diameter.
BUDGET: No funds have been budgeted for any improvements at this time.
RECOMMENDATION: No action recommended.
REVIEWED BY CITY P