ABOUT SEPTIC TANK AERATORS/AIR PUMPS
(If you don't need the following information and just want
to buy an air pump now, click here: "Septic Aerator Air Pump Store" )
"McComb Septic Tank Aerators, Air Pumps, Blowers & Air
In McComb we often hear the words above used interchangeably to describe the apparatus that
provides air to the waste water treatment plant. The most accurate term is "Air Pump", and it's function
is to generate a constant flow of air to the aeration system by way of a 1/2" pvc pipe that leads to the first
chamber of the modad treatment plant. Inside this chamber, the pvc pipe is directed downward about 5.5 feet to
within inches of the bottom of the tank and then branches out forming a tee with numerous drilled holes to allow
the air from the air pump to diffuse through the liquid sewage from bottom to top much as an aquarium aerator
"Why Do Waste Water Treatment plants In McComb
Need Air Pumps And Aeration Systems When Septic Tanks Don't?"
The city of McComb and all other cities in Mississippi are required to use Aeration Systems
and air pumps for all commercial and residential waste water treatment plants (MODADS). So why is this requirement
made? What is the advantage?
The reason and the advantage is that sewage treatment plants with an aeration system give
an effluent of about 95% clean water, while the trusty septic tank, without aeration, discharges water that is only
45 to 65% clean. This is not to say that you should be hooking up your sewage treatment plant discharge line
to your potable water line anytime soon!!! But it is a very powerful outcome to what seems like a very simple
add-on. Let's go over the differences between how the septic tank and sewage treatment plants (with aeration)
break down sewage waste.
"The McComb Septic Tank Without An Air Pump and Aeration
In McComb, the "septic tank" is a round cylinder or square tank that has only a single chamber.
The septic tank utilizes naturally occurring anaerobic bacteria to breakdown the waste water. They are called
"anaerobic" because they decompose sewage waste without air (oxygen). it should be no surprise that these same
anaerobic bacteria are already at work in our digestive system well before coming to the septic tank! (what a
The septic tank anaerobic process breaks down sewage through Hydrolysis (adding water), that
sets off fermentation which first produces acetic acid, Hydrogen and carbon dioxide. This in turn gives rise to
ammonia, methane gas and the inevitable rotten egg smelling hydrogen sulfide gas, that gives us such a fond
attachment to the septic tank! Of course we too give off the same gases through the same processes. How does it
feel to know that we are all little walking septic tanks??!!!
So if all this harmless gas is given off, surely the outcome must be a clean water
discharge...far from it. Actually the anaerobic process water discharge is full of minute, still soluble
(undigested) particles. Added to this acetic acid, ammonia and hydrogen sulfide gas all remain in the water. Such a
mix, and with little or no oxygen. Can you imagine what large amounts of water like this would do to any organisms
living in it...like fish for instance??!
Since we do live in McComb and know what swamp land is like, we can now understand why the water
in these areas can look brown and smell so bad. You guessed it...because all the organic matter sinks to the sludgy
bottom and begins the anaerobic process of fermentation. The smell is that hydrogen sulfide gas. The color of the
water is due to the acetic acid that leaches the tannin (brown) pigment from the plant material as it
"The McComb Waste Water Treatment Plant With An Air Pump
and Aeration System"
All septic tanks in McComb are now being replaced with the waste
water treatment plants with a modad air pump and Aeration System. The drawing below is the typical set up for these
plants. As you can see in this example, the tank has two chambers (although some have three); the first is the
Aeration Chamber, where air from the air pump is directed to the bottom of the tank through a 1/2" pvc pipe that
tees off there and releases bubbles up through small holes drilled in the pipe.
The purpose of all this is to agitate and thoroughly aerate the incoming waste water. This
allows the aerobic bacteria or bacteria that need oxygen to decompose and transform the waste water into something
realtively clean to do their work.
Now let's trace the path of the incoming sewage. As we have seen, it first enters the aeration
chamber to be oxygenated. Before going further it is important to understand that the Waste
Water Treatment plant, like the septic tank is an overflow system. This means that contrary to what most
people think, the modad tank is always full! The inlet pipe you see coming into the tank from the house is set up
about 4" above the waste water level in the tank. The outlet pipe you see leaving the tank by way of the
clarification chamber is set 4" lower than the inlet pipe from the house. This maintains a constant waste water
level by way of an overflow. What this means is if, for instance, you flush a toilet, the 3 gallons going into the
Aeration Chamber will have give rise to 3 gallons going out of the treatment plant Clarifier Chamber
overflow. So you see, the treatment plant is always full, but in a constant state of water moment as you input
Now back to the waste water coming into the Aeration chamber. The organic solids, oils and
greases in the sewage will be buoyant and remain on the surface until they are digested by aerobic bacteria. Then
every time your waste water enters the treatment plant from the house, the digested waste water below the solid
floating wastes are circulated down and out through the 4" to 6" space under the separation wall (Baffle) shown
above and into the Clarifier Chamber. Remember, 3 gallons entering the waste water plant means 3 gallons going out
the Clarifier chamber outlet pipe. The Clarifier Chamber is just that; In the intervals when sewage is not
circulation into the treatment plant, the now digested waste water in the Clarifier Chamber settles out, in that
any heavy particulates fall to the bottom leaving the clearer water on the surface to be pushed out upon the next
waste water entering into the plant from the house. Now what are the results?
If working according to design, this process will not give off methane, hydrogen sulfide (stinky
gas) or acetic acids like the anaerobic bacteria of the septic tank, but rather carbon dioxide and minute particles
of insoluble (already digested) solids, along with nitrates and sulfates. Best of all, the discharge water will
leave the tank in an oxygenated state which will not be harmful to aquatic animals.
"In McComb It Makes Sense To Have A Waste Water Treatment Plant And To
Make Sure Your Air Pump, Aerator Is Working Properly"
We have seen from the results of the
Waste Water Treatment Plant in McComb that it makes good sense to ensure your air pump, aerator is working
properly. How do we do this and what are problems with the different kinds of air pumps, aerators and
"What Types of Air Pumps-Aerators-Blowers are there in
McComb and which is the best for your Waste Water Treatment Plant?"
oldest types of aeration devices in McComb are probably the "Mixer Aerator" and the "Rotary Blower" pictured
Rotary Blower Aerator Mixer
The Rotary Blower is an excellent aerator that puts out more air than any other type of aerator,
but like the mixer aerator to the right, both have the disadvantage of having large electric motors that consume a
lot of electricity and so are expensive to run 24 hours a day. For this reason, they are usually put on a timer to
save on energy and run many on and off cycles during the day. This presents another problem of increased wear to
the starter condenser of the electric motor and to the starter switch contact and failures of these are
If you still have one of these two types of aerators, it is probable that they are no longer
working. Add to this the certified replacement aerators are often no longer available. Consequently, most of the
sewer treatment plant manufacturers have now certified the newest type of air pump aerator called the "Linear
Diaphragm Air Pump" (shown below) for their respective treatment plants.
Linear Diaphragm Air Pump
The Linear Diaphragm Air Pump is much like the smaller vibrating
aquarium air pump. It works as shown in the following animation. This is a very simple, efficient pump that usually
works 24 hrs per day for 3 to 5 years without a problem. After this time the plastic diaphragms are worn and may be
replaced with an inexpensive kit.
The size of these linear pumps in McComb depend on the
specifications required by the respective Modad sewer treatment plant make and model. The usual specifications are
given in Liters per minute and is the volume of air pumped at between 2 and 4 psi pressure. Residential sewer
treatment plants utilize Linear Diaphragm Air Pumps of between 40 and 100 Liters Per Minute at 2.13 psi. The
following shows the dimensions and weights of the different sized pumps:
"The National Sanitation Foundation (NSF) And
Certification of Aerator, Air Pumps For Waste Water Treatment Plants in McComb"
As we have seen, the Linear
Diaphragm Air Pump is the best modern air pump for aeration in residential sewage treatment plants in McComb.
However, the National Sanitation Foundation (NSF) is the governing body that certifies which size, make and model
of air pump may be "legally" used for each make and model of Modad sewer treatment plant.
This is all to say that even though there are many
compatible linear Diaphragm Air Pumps manufactured that give exactly the same volume and pressure as the NSF
"Certified" Linear Diaphragm Air Pumps, only the "Certified" pumps are "Legal". And "Legal" means, at least in
McComb, Mississippi, that if you sell your house you must have the "Certified", "Legal" air pump specified for your
Modad Sewer Treatment Plant installed.
Naturally, these certified linear diaphragm air
pumps are more expensive than other compatible linear Diaphragm air pumps with exactly the same specifications. So,
if you are not expecting to sell your house within five years or so, your selection of a more economical pump might
be warranted. We do sell both certified and uncertified air pumps for this purpose.
Aerator Air Pump Store In McComb!"
OK, now that you know everything that you need to know about Aerators and Air
Pumps in McComb, click here and take a look at the air pumps we offer:
"Septic Aerator Air Pump Store"