City of
Wayne Source Water Assessment
Worms In His Coffee?
Examples Where Back Flow
Occurred
Picture of a Cross-Connection Found
in Wayne
What Is Thermal Expansion?
Arsenic Rule
City of Wayne Source Water
Assessment
The 1996 Safe Water Drinking Act Amendments
established a strong new emphasis on preventing contamination problems through
source water protection and enhanced water systems management. The goal of
Nebraska’s Source Water Assessment Program is “To develop information which
enables Public Water Supply owners, consumers, and others to initiate and/or
promote actions to protect their drinking water sources.” The Source Water
Assessment Program is a federally mandated program that requires the
assessments to be made available to the public. The Source Water Assessment for
the City of Wayne is complete and can be viewed at the City of Wayne’s Clerk’s
office between 9:00 AM and 5:00 PM daily.
Worms in His Coffee?
(Homeowner finds nematodes in his water)
By Gene Regan
Texas Natural Resource
Conservation Commission
Article from ABPA News
January/February 2002 Volume 15
Issue 1
A Keller, a Texas homeowner was surprised to find dozens of squiggly worms
in his upstairs toilet bowl recently. Later, as he was pouring water into his
coffee maker, he noticed something moving in the water – another little worm.
He collected samples of the worms and presented them to Angela Wallis,
Environmental Services Coordinator for the City of Keller Water Utilities
Department. Angela, who is also a Certified Backflow Prevention Assembly
Tester, advised him they were nematodes and that they most likely came through
his landscape irrigation system.
It turns out the irrigation system had a nine-year old double check valve
assembly (DCA) that had not been tested since it was installed. When the
homeowner tried to turn off the water to the irrigation system at the device,
both gate valve handles crumbled. He was able to turn one valve off with a
wrench, though.
The story gets a little more interesting. When the homeowner contacted a
company to test the DCA, the person who arrived to do the test told him it
would be cheaper to replace the device than to test it. $275 later, he had a
new DCA. However, the homeowner later discovered that the company did not
obtain a permit from the city, nor had they tested the new device.
At the time of this writing, Ms. Wallis is investigating possible City of
Keller ordinance violations. The TNRCC Landscape Irrigation Program is
inquiring into possible violations of State law.
Top of the Document
Examples Where Backflow
Incidents Occurred
In 1932, in the worst case in Nebraska history, during a 5-week period more
than 10 percent of the 347 children in Huskerville, NE, contracted polio. A
study of the water revealed that the afflicted children lived in areas where
flush valve water closets lacked vacuum breakers. A time relationship was found
also in places where extreme fluctuations of pressure in the water mains might
have permitted wastewater to be forced in the drinking water supply.
80 students at a midwestern university reported remittent fevers, malaise,
headache and anemia. Their symptoms led to a diagnosis of undulant fever
(brucellosis). Only those students who had been working in the cultivation of
bacteria in one of the laboratories were affected. The mystery was how the
brucella cultures in the laboratory could have been transmitted to the
students. Finally, a hose was found connected to a faucet in the laboratory.
The other end of the hose was submerged in water containing brucella. A
temporary reversal of pressure, possible the consequence of a demand for water
in another part of the system, had drawn the water teaming with brucella into
the drinking supply. Of the 80 students affected, 1 died. As you can see, the
problem we are dealing with can have deadly results.
In 1972 in a west coast industrial plant, a submerged inlet was used to
supply a lye vat with water. On the other side of a wall from the vat was the
employee’s shower room. Fortunately, the cross connection was discovered before
harm was done. However, company officials were alarmed that employees could
have been taking showers with water contaminated with lye from the vats.
In a case involving an automatic car wash, gallons of concentrated detergent
were injected into a city water system. The detergent was found in resident’s
drinking water more than a block away. The cause was reported as an unprotected
cross connection in the car wash plumbing lines.
In Newton, Kansas, in 1942, one of the town’s two water supply mains had
been taken out of service on September 2, 7 and 8. A house service connection
to this main supplied three frost-proof hydrants, and two frost proof toilets.
It was assumed, from subsequent events that some unknown person or persons
tried to obtain water from a hydrant connected to the main out of service. When
no water flowed the person evidently left, leaving the valve open. On September
10, it was discovered that a neighboring sanitary sewer was clogged and the
sewage had overflowed into the hydrant box. It was learned that for two days,
all the sewage from the toilets of ten families had been permitted to flow into
the water main. When the main was put back into service, there was no attempt
to sterilize it. More than 2,500 persons in all parts of the town suffered
enteric disorders as a result. Stool cultures and pathological findings from
two autopsies diagnosed the illness as bacillary dysentery. In addition to the
widespread illness in the town, it is believed that the infection was carried aboard
a number of troop trains, which were watered in Newton at that time.
Backsiphonage caused by defective plumbing in a new student nurses building
was blamed for an outbreak of disease in 1963 in Ohio. It was necessary for 100
of the student nurses to be quarantined for two weeks. Bacteriological
examination showed that the drinking water was contaminated. The city health
commissioner theorized that salmonella was brought into the building by some of
the girls and then spread by defective plumbing.
A tank truck filling from a city water supply caused a serious emergency
involving the contamination of a water supply. In 1971, a contractor using a
tank truck with a rig designed to pump and spray a mixture of water,
fertilizer, grass seed and wood pulp working on the grounds of a subdivision.
The contractor was using a direct connection to a fire hydrant to fill the tank
with water, which was then mixed with the fertilizer and other ingredients. A
high-pressure pump then mixed with the fertilizer and other ingredients. A
high-pressure pump then sprayed the mixture onto the ground. As the wood pulp
circulated through the tank piping system, it plugged one of the lines while
the pump continued to run, creating a very high pressure in the tank. This
pressure was higher than the water supply system pressure and forced the
solution of fertilizer into the water supply. Several people in the subdivision
became ill after drinking the water, but the contamination was discovered and
quick action in flushing and disinfecting the lines eliminated the danger.
Eleven caddies experienced nausea, severe vomiting, and abdominal cramps
after consuming a “soft drink” at a New York golf club in 1964. The beverage
was commercially prepared by the mixture of syrup with carbonated water in a
vending machine. Investigation revealed that a pipe carrying water into the
machine was connected to the recirculating hot water system instead of the
drinking water system. The day before the incident, a lye and chromate solution
was added to the hot water system.
A New England town had two separate water systems – one for safe drinking
water, and the other for fire protection. The fire protection system pumped
untreated water directly from a river. At an industrial plant in town, workers
mistook a fire system line for a fresh water line and connected a bubbler to
it. After drinking the water from the bubbler, seven people developed
infectious hepatitis and over a hundred people were ill with gastroenteritis.
In 1967, an outbreak of gastroenteritis occurred at a small private college
in Pennsylvania. Almost one quarter of the 700 students and faculty were
affected. The only factor in common to all those who became ill was the
consumption of water or food that had been prepared using water from the school
water system. Investigation of the water system revealed that a water line had
broken in the kitchen of the school cafeteria, flooding both the kitchen and
the cafeteria. Cross connections were found between the sewage system and the
water system that could have resulted in backsiphonage of sewage into the water
system as a consequence of negative pressure during the break in the water
line. It was concluded that the outbreak probably resulted from the presence of
Shigella Sonnei in the water system. The incoculum would have been of
sufficient size to overcome the chlorine in the water.
At a large aviation plant on the west coast, officials learned that the
difference between a 3-inch water main and an 8-inch water main was the
determining cause for a high rate of absenteeism. When it was discovered that
25-40% of the employees were suffering from gastroenteritis, the plumbing
system was suspected. Investigators found that there was such a demand on the
3-inch main at peak periods that the outflow produced enough of a vacuum to
allow wastewater to be backsiphoned through cross connections into the drinking
water system. After an 8-inch main was installed, the high rate of infection
subsided
About 2 p.m. on June 29,1960 on a large pier installation in an eastern port
harbor, a worker noticed evidence of salt in the public water supply.
Investigation showed that salt water from the harbor had been pumped into the
pier’s potable water pipes. The fire systems of three vessels anchored nearby
had been connected to the public water piping system and high fire-pump
pressures apparently did the rest. One measurement of chlorides at a public
water outlet showed 6, 425 parts per million. Only prompt and vigorous action
by a sanitary engineer is believed to have prevented widespread illness.
Top of the Document Top of this Section
The following pictures were taken right
here in Wayne. You can see that the drinking water system is connected directly
to sewer system. This is a direct cross-connection. This is an instillation of
a reverse osmosis water purification unit by Culligan.
Thermal Expansion
When a water heater heats water, it expands. If a check valve, pressure
reducing valve, or other device does not block the inlet to the water heater,
the increase in volume simply travels back into the water source. If the inlet
is blocked, this increase in volume will cause an increase in pressure,
sometimes to dangerous levels. The T&P valve should relieve this pressure
by discharging some water. A thermal expansion tank can be installed in
the water line that will absorb the increase in volume preventing the relief
valve from discharging water unnecessarily.
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SYMPTOMS
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·
Effects are only noticeable after hot water use followed by periods of
no water use.
·
Relief valve drips during any recovery cycle when no hot or cold water
is used.
·
Hot water pipes creak while heater is recovering and all valves are
closed.
·
Tanks or other components of the water supply system fail prematurely.
·
A metallic creaking noise might actually be heard in the location of
the heater as the pressure is relieved and the stretched tank returns to a
natural shape.
·
Faucet drips during any recovery cycle when no hot or cold water is
used.
·
Water surges when a valve is first open and then pressure drops.
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CAUSE
|
The water in a water heating system expands when it is heated and has a
greater volume. Since water will not
compress (like air), system designers must include provisions for thermal
expansion. (Water in a closed tank at
50 psi, when heated just 10 degrees, will reach a pressure of 250 psi).
Many water supply systems have check valves at the water meter to prevent
any possible contamination of the public water supply by the accidental
back-flow of contaminated water into the supply mains. These check valves are often required by
code, and some cities are even installing the check valves. They serve a useful purpose. Do not remove them!
The use of pressure reducing valves (PRV) is another cause. PRVs are designed to conserve water and
prolong fixture life. Many PRVs also
act as very effective check valves.
Again, do not remove them!
Water softeners in the system may also act as back-flow preventers.
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TEST
|
Follow these easy steps to diagnose thermal expansion:
·
Turn the
heater thermostat all the way down, and install a water pressure gauge with
dead hand (AOS part #4798) on the drain valve. Open the drain valve, so the gauge reads system pressure.
·
Open a hot
water tap and allow 15% to 20% of the tanks volume to run out. Shut off the drain valve and make sure
that no other fixture in the system, hot or cold, is open. Make sure that outside fixtures, if they
are on the same system, are turned off too.
Any water leaks or use will make the test meaningless.
·
Check the
water pressure gauge, and turn the pointer so it lines up with the
pressure-indicating needle. Turn the
thermostat back up to its normal position, so the heater cycles on. Watch the pressure gauge.
·
If the system
is closed, the pressure will start to climb steadily and rapidly. A small amount of thermal expansion
control may be built into the system because of trapped air pockets or a
water hammer arrestor. In that case
the pressure will increase slightly, hold steady for a short time and then
rapidly increase. The temperature and
pressure relief valve (T&P) or PRV should open and release water once the
pressure reaches the maximum setting on the valve. The valve will close once the pressure falls below the pressure
setting of the valve.
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THE FIX
|
The ideal fix involves the use of a pressure-reducing valve if supply
pressures are above 60 to 70 psi, and a properly sized expansion tank. The PRV reduces supply pressures to 40 to
60 psi allowing an economically priced and sized expansion tank to be
used. The PRV also offers the benefit
of saving water and prolonging the life of water flow valves. The PRV is not required if the system already
has one or if high supply pressures are desired.
The PRV is installed between the check valve and the water heating
system. The expansion tank is
installed between the PRV and the water heating system. Follow the manufacturer's instructions for
installing the expansion tank.
Run the thermal expansion check again.
The pressure should increase only slightly then hold steady throughout
the recovery cycle. The expanded
water is flowing back from the heater and into the pressurized storage
bladder of the expansion tank. Air
pressure will force this water out of the expansion tank into the supply once
usage resumes.
DO NOT DEPEND ON THE T&P VALVE TO HANDLE THERMAL EXPANSION! The T&P valve, according to the makers
of those valves, was designed as an emergency relief device only. The T&P could be subject to reduced
effectiveness or failure.
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FIGURE
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WARNING
|
Thermal expansion of water, if not compensated for in
system design, will lead to the early failure of components. These failures are not covered by the
manufacturer’s warranty, so it is extremely important that everyone be aware
of the causes, symptoms and solutions to thermal expansion in a closed water
heating system.
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EPA Finalizes Arsenic Rule
New
standard could affect as many as 80 Nebraska water systems.
By
Lash Chaffin
Utilities
Section Director
League
of NE Municipalities
(From
the December 2001 issue of the Nebraska Municipal Review)
After a very rapid series of events, on
Oct. 31, 2001, Christine Whitman, Administrator of the (EPA), announced that
the final drinking water arsenic standard will be 10 ppb. For most
municipalities, the earliest effective date will be January 2006, but there are
a few questions remaining about the actual date.
This standard could affect as many as 80
Nebraska water systems, and the cost to these systems could be $95 to $110
million.
This action took place shortly after the
third of three studies mandated by congress was completed. Prior studies by the
EPA National Drinking Water Council and Arsenic Rule Benefits Review panel of
EPA indicated that for the most part EPA’s methodology in originally setting
the standard at 10ppb was sound.
The third study by the National Academy
of Science National Research Council reported that the risks from arsenic are
even greater than those estimated by EPA in January. The Committee found that
men and women who daily consume water containing 3 parts per billion of arsenic
have about a 1 in 1,000 increased risk of developing bladder or lung cancer
during their lifetime. At 5 ppb, the risk is about 1.5 in 1,000; at 10 ppb, it
is greater than 3 in 1,000; and at 20 ppb, it is close to 7 in 1,000. According
to the American Water Works Association, EPA generally issues regulations with
a cancer range of 1 in 10,000 to 1 in 1,000,000. However, this is a policy and
is not part of the Safe Drinking Water Act.
Strengthen
Standard
In announcing the new standard, Whitman
said: “throughout this process, I have made it clear that EPA intends to
strengthen the standard for arsenic by substantially lowering the maximum
acceptable level from 50 ppb, which has been the lawful limit for nearly half a
century. The Bush Administration is committed to protecting the environment and
the health of all Americans.”
According to an EPA estimate, nearly 97%
of the water systems affected by this rule are small systems that serve less
than 10,000 persons. EPA also released a fact sheet estimating that about 4,000
water systems will have to take steps to meet the lower standard at an annual
average household cost of $32, noting that the cost will be substantially
higher (ranging for $58 - $327) for systems serving fewer than 3,300 people.
Nebraska HHSS Regulation and Licensure has released estimates that systems in
Nebraska serving fewer than 500 persons could spend as much $1,600 annually to
comply with the rule.
EPA plans to provide $20 million over the
next two years for the research and development of more cost-effective
technologies. The agency also will provide technical assistance and training to
operators of small systems, which will reduce their compliance costs. EPA will
work with small communities to maximize grants and loans under current State
Revolving Fund and Rural Utilities Service Programs of the Department of
Agriculture.
Requires One Sample
This regulation will require one sample
from each point of entry during three-year compliance periods for groundwater
systems, and one sample from each point of entry annually for surface water
systems. Systems that exceed the MCL will be placed on quarterly monitoring
schedules. Compliance for systems on quarterly monitoring will be based on a
running annual average. Arsenic results must be included in a system’s 2001
Consumer Confidence Report. Monitoring waivers will be available based upon
prior samples, source water vulnerability and system characteristics.
Nebraska’s congressional delegation
issued a joint statement criticizing the action to lower the arsenic standard
stating that it will cost Nebraskans millions of dollars and won’t necessarily
make water safer. There are numerous congressional efforts being conducted to
provide some funding for compliance with this rule. It is also possible that
some members of Congress from other states might attempt to lower the standard
below 10 ppb.
This issue will continue to develop over
the next couple of years, so it is important that your municipality continue to
follow League of NE Municipalities publication to stay informed.
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