PETAL, MS - Two men killed Tuesday afternoon at a lift station in Petal have been identified.
Forrest County Deputy Coroner Lisa Klem said the victims were Terry West, 45, and his son, Gage West, 20, both of Brandon.
The two men are believed to have been overcome by methane gas while working at the lift station. Their actual cause of death is pending autopsy results, Klem said.
Mayor Hal Marx said the men were working for a company that had contracted with the city to do some work at the lift station on Short South Street.
"Our crew was on the scene with them most of the day," he said. "They told our crew they could leave and they were finishing up."
Marx said two of the three men working for the contractor were found unconscious in the lift station.
Emergency personnel were called. First responders were able to reach the men, who were about 15 feet down, and pulled them out.
Efforts to revive the men were unsuccessful.
Marx declined to give the name of the company the men worked for.
Carolyn McAfee, who lives next to the lift station, said she could not get to her home for about an hour while emergency personnel worked to get the men above ground.
"It was sad, just sad," she said. "My heart goes out to their families.
"Their husband, their son, their father left home this morning, and they aren't coming back."
She said once she learned it was gas that killed the men she became concerned about her health and safety.
"I was told it was odorless gas," she said. "I am concerned about my health and my neighbors' health.
"And is it safe for me to stay in my house tonight?"
Marx said he wanted to reassure residents they are in no danger.
"The problem was with the workers being in a confined space with the sewer water," he said. "It was not a gas leak."
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PETAL, MS (WDAM) -
Two people are dead in Petal after an incident on West 7th Avenue.
Two contractors working for the city were working on a lift station when officials believe they were overcome by methane gas, according to Petal Mayor Hal Marx.
Marx said the workers were 15 feet deep in the lift station at the time of the incident.
The fire department tried to save the men, but did all that they could do, according to Marx.
Marx said officials believe because the gas was odorless the workers were unable to react quickly enough.
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PETAL, Miss. (WHLT) — A Brandon father and son were killed by methane gas while working at a lift station in Petal, according to officials.
Forrest County Deputy Coroner Lisa Klem said 45-year-old Terry West and 20-year-old Gage West were the two men who died.
We’re told the two men were working at a wastewater pump on Tuesday when the incident happened.
Petal Mayor Hal Marx said the men were working for a company that contracted with the city.
Marx said the two of the three men working for the contractor were found unconscious in the lift station. Attempts by emergency first responders to revive Terry and Gage West were unsuccessful. They were pulled out from about 15 feet down, according to authorities.
Marx said the problem wasn’t a gas leak but that the workers had been in a confined space with the sewer water.
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What is a Lift Station?
Posted by Randy Hollenbeck on April 17, 2013
DPW, Water, Sewerage
Pumping stations in sewage collection systems, also called lift stations,
are normally designed to handle raw sewage that is fed from underground
gravity pipelines (pipes that are sloped so that a liquid can flow in
one direction under gravity). Sewage is fed into and stored in an underground pit, commonly known as a wet well. The well is equipped with electrical instrumentation to detect the level of sewage present. When
the sewage level rises to a predetermined point, a pump will be started
to lift the sewage upward through a pressurized pipe system called a sewer force main or rising main from where the sewage is discharged into a gravity manhole. From here the cycle starts all over again until the sewage reaches its point of destination—usually a treatment plant. By this method, pumping stations are used to move waste to higher elevations. In
the case of high sewage flows into the well (for example during peak
flow periods and wet weather) additional pumps will be used. If this is insufficient, or in the case of failure of the pumping station, a backup in the sewer system can occur, leading to a sanitary sewer overflow—the discharge of raw sewage into the environment.
Sewage pumping stations are typically designed so that one pump or one set of pumps will handle normal peak flow conditions. Redundancy
is built into the system so that in the event that any one pump is out
of service, the remaining pump or pumps will handle the designed flow. In these days there are a lot of electronic controllers in the market designed specially for this application. The
storage volume of the wet well between the "pump on" and "pump off"
settings is designed to minimize pump starts and stops, but is not so
long a retention time as to allow the sewage in the wet well to go septic.
Sewage pumps are almost always end-suction centrifugal pumps with open impellers
and are specially designed with a large open passage so as to avoid
clogging with debris or winding stringy debris onto the impeller. A four pole or six pole AC induction motor normally drives the pump. Rather
than provide large open passages, some pumps, typically smaller sewage
pumps, also macerate any solids within the sewage breaking them down
into smaller parts which can more easily pass through the impeller.
The interior of a sewage pump station is a very dangerous place. Poisonous gases, such as methane and hydrogen sulfide, can accumulate in the wet well; an ill-equipped person entering the well would be overcome by fumes very quickly. Any entry into the wet well requires the correct confined space entry method for a hazardous environment. To
minimize the need for entry, the facility is normally designed to allow
pumps and other equipment to be removed from outside the wet well.
Traditional sewage pumping stations incorporate both a wet well and a "dry well". Often these are the same structure separated by an internal divide. In
this configuration pumps are installed below ground level on the base
of the dry well so that their inlets are below water level on pump
start, priming the pump and also maximizing the available NPSH. Although
nominally isolated from the sewage in the wet well, dry wells are
underground, confined spaces and require appropriate precautions for
entry. Further, any failure or
leakage of the pumps or pipework can discharge sewage directly into the
dry well with complete flooding not an uncommon occurrence. As
a result, the electric motors are normally mounted above the overflow,
top water level of the wet well, usually above ground level, and drive
the sewage pumps through an extended vertical shaft. To
protect the above ground motors from weather, small pump houses are
normally built, which also incorporate the electrical switchgear and
control electronics. These are
the visible parts of a traditional sewage pumping station although they
are typically smaller than the underground wet and dry wells.
More modern sewage pumping stations do not require a dry well or pump house and usually comprise only a wet well. In
this configuration, submersible sewage pumps with closely coupled
electric motor are mounted within the wet well itself, submerged within
the sewage. Submersible pumps
are mounted on two vertical guide rails and seal onto a permanently
fixed "duckfoot", which forms both a mount and also a vertical bend for
the discharge pipe. For
maintenance or replacement, submersible pumps are raised by a chain off
of the duckfoot and up the two guide rails to the maintenance (normally
ground) level. Reinstalling the
pumps simply reverses this process with the pump being remounted on the
guide rails and lowered onto the duckfoot where the weight of the pump
reseals it. As the motors are
sealed and weather is not a concern, no above ground structures are
required, excepting a small kiosk to contain the electrical switchgear
and control systems.
Due
to the much reduced health and safety concerns, and smaller footprint
and visibility, submersible pump sewage pumping stations have almost
completely superseded traditional sewage pumping stations. Further,
a refit of a traditional pumping station usually involves converting it
into a modern pumping station by installing submersibles in the wet
well, demolishing the pump house and retiring the dry well by either
stripping it, or knocking down the internal partition and merging it
with the wet well.
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Everything You Always Wanted to Know About Sewer Gas...But Were Afraid to Ask
Question: What is sewer gas?
Answer: Sewer gas, at least that which causes an odor problem to the
occupants of a house, is a mixture of inorganic gases created by the
action of anaerobic (needing no oxygen) bacteria on sewage and sludge.
This gas can contain hydrogen sulfide, ammonia, carbon dioxide, methane,
nitrogen, and hydrogen.
Question: What makes it smell so bad?
Answer: Almost always, hydrogen sulfide is the odor culprit,
although ammonia may be formed in rare cases. The rest of the gases
listed above are odorless. The odor threshold, the lowest concentration
that can be detected with the nose, for hydrogen sulfide is somewhere
between .001 and .01 parts per million (ppm), an extremely low
concentration. As an illustration, 1 ppm on a linear scale is one inch
in 15.8 miles.
Question: Can these gases harm the people who come into contact with them?
Answer: Only under extremely unusual circumstances. Although
hydrogen sulfide is a toxic gas, it will not harm people at the
concentrations that exist in a house with sewer gas odor problems.
Studies have shown that hydrogen sulfide has a depressant effect on the
central nervous system in concentrations above 150 ppm. This is 15,000
to 150,000 times the amount detectable by most people. Not enough gas
is generated in the sewers for concentrations to approach the dangerous
level in the dwelling.
However, if a person were to enter a tunnel or deep hole that contained
sewage undergoing anaerobic breakdown, there is a chance he could
become poisoned.
Question: How does it get into the house?
Answer: The only way sewer gas can get into a home is if there is
something wrong with your plumbing. The most common fault in the
plumbing system is untrapped drains, especially floor drains in the
basement or utility room. Since 1970, the City of Marion has had a
plumbing inspection program and any houses built after that year should
have no problem with a lack of traps. If your house is older than that,
your floor drains may or may not be trapped.
Other ways sewer gas can get into your home include:
-
A dry trap. If there is a trap in a drain line that is not often
used, the water in the trap may evaporate, breaking the trap seal.
-
A damaged trap. Obviously, if the trap is cracked and allows the water to run out, the trap seal is again lost.
-
A damaged drain line. If the drain line is cracked or broken between
the main sewer and the trap, there is nothing to impede the flow of
gases through the crack or break in the line. Also, a damaged drain
line may allow sewage to drain into the basement or crawlspace under
your house, and you may get a sewer odor from that accumulation of
sewer.
-
A damaged or plugged vent. The vent system in your plumbing is
designed to equalize the atmospheric pressure differences caused by
wastewater flowing through the plumbing, and also to allow sewer gases
to escape the plumbing system by venting them into the atmosphere above
the house. If this system has an untrapped opening inside your house,
gases may escape through that opening.
If the vent is plugged or absent, those unequal pressures it was
designed to eliminate may siphon the water out of the trap to such an
extent as to ruin the trap seal.
Question: How is it produced in the sewer?
Answer: Hydrogen sulfide (H2S) is produced when the sulfate radical
(SO4) is reduced to H2S and H2O (water). This reaction can take place
only when there is no oxygen or other oxidants in the microbial
environment. Studies have shown that H2S is not produced in fresh
wastewater for two or three days, by which time it is normally to or
through the wastewater treatment plant.
There are, however, some environments where hydrogen sulfide is produced in the sewers:
-
The slime layer that coats the sewer pipe below the water line.
Although this layer can be only .040 of an inch thick, the
three-quarters of the layer closest to the sewer pipe is so oxygen-poor
that H2S is commonly formed.
-
If any sludge has been deposited at the bottom of the pipe, H2S will also be formed in that sludge.
-
If there is a problem in the sewer with flow (if it is plugged or
partially plugged) so that the sewage cannot keep moving, the oxygen
content gets to low that H2S can be produced in the sewage itself.
An important point to remember is hat all sewage systems, at one time or another, produce sewer gas.
Question: What can be done to keep it from being formed in the sewers?
Answer: If the hydrogen sulfide is becoming a problem in a very
localized area (for example at the treatment plant or at a lift
station), oxidizers can be added to the sewage to increase the
oxidation-reduction potential. These oxidizers can be oxygen, hydrogen
peroxide, chlorine, permanganates, and others.
If the problem is in part of the sewage collection system, about all
that can be practically done is to flush the sewers in order to increase
the flow rate and remove any sediments or obstructions. However, this
can only be done to alleviate acute problems, and is not practical on a
continuous basis.
Question: What can I do to keep odors out of the house?
Answers: The best answer is to find the problem with the plumbing
system and have it repaired. If the floor drains are untrapped, have
traps installed. It is probably not wise to simply plug the drain,
because any water that enters the basement or utility room will have no
place to go and possibly flood the room. In any case, an experienced
plumber will be able to find the shortcomings of the system and offer
suggestions on how to correct them on an individual basis.
Question: What, exactly, is a trap?
Answer: A trap is a device made from a U-shaped section of pipe,
tubing or tile which traps wastewater. This wastewater then acts as a
seal to prevent sewer gases from coming out through the drain opening.
Question: How can I tell if my floor drains are trapped?
Answer: Pour water into the opening (at least 2 gallons) and
visually inspect by looking down the opening. If there is considerable
water standing (so that it fills the pipe), then the drain is trapped.
Check it again a couple of hours later to be sure the water hasn’t
drained out.
If there is no standing water, then either there is no trap or it is
located somewhere else in the line. If there are odors present, pour
some water into the opening and check for odors about an hour later. If
the odors are still present, there is probably no trap.