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How Septic Systems Work

The septic tank serves as a settling basin where solids accumulate and gradually get broken down by bacterial action.

Some of the solid waste is actually liquefied by this "natural bacterial decomposition," however the rest of the waste accumulates in the bottom as a layer of sludge. Additionally, a small percentage of this waste (mostly fats and oils) floats to the top of the tank to form a layer of semi-solid scum.

What Are Septic Tanks?
Septic Field Diagram - Williams & Bay Pumping

The population living in metropolitan areas (who have never had the pleasure of maintaining a septic system, or who have never experienced waddling in their leachfield, or even had the experience of pumping out their systems) simply flush their toilets and "away go troubles down the drain."

Those of us living in more rural areas have been forced to learn about the maintenance and workings of the sewerage treatment facility attached to our home, "the septic system." Usually a septic tank is connected to a drainage field or seepage pit of some kind. If properly maintained, a well-designed system will last almost indefinitely. However, if it is neglected for too long, it can back up and clog the drainage field. This neglect can result in an expensive excavation and even replacement of the drainpipes that could cost thousands of dollars.

Septic System Diagram - Williams & Bay Pumping
How Do Septic Tanks Work?


A typical household sewage treatment system consists of a house sewer, septic tank, distribution box and absorption field or seepage pit.

House Sewer - The pipeline connecting the house and drain and the septic tank.

Septic Tank - Untreated liquid household wastes (sewage) will quickly clog your absorption field if not properly treated. The septic tank provides this needed treatment. When sewage enters the septic tank, the heavy solids settle to the bottom of the tank; the lighter solids, fats and greases, partially decompose and rise to the surface and form a layer of scum. The solids that have settled to the bottom are attacked by bacteria and form sludge. Septic tanks do not remove bacteria and, therefore, what is discharged cannot be considered safe.

Distribution Box - Serves to distribute the flow from the septic tank evenly to the absorption field or seepage pits. It is important that each trench or pit receive an equal amount of flow. This prevents overloading of one part of the system.

Absorption Field - A system of narrow trenches partially filled with a bed of washed gravel or crushed stone into which perforated or open joint pipe is placed. The discharge from the septic tank is distributed through these pipes into trenches and surrounding soil. The subsurface absorption field must be properly sized and constructed. While seepage pits normally require less land area to install, they should be used only where absorption fields are not suitable and well-water supplies are not endangered.

Cesspools - Work in a similar manner to septic systems. Sewage water usually seeps through the open bottom and portholes in the sides of the walls. These can also clog up with overuse and the with the introduction of detergents and other material which slow up the bacterial action.

When the sewage backup occurs, homeowners usually have the system pumped out. Pumping out will only relieve the system temporarily. The clogged pores in the ground remain and eventually the system will have to be pumped again and again.

Components Of Sewage Treatment Systems
Cesspool Diagram - Williams & Bay Pumping

Since solids will continue to build up at the bottom of the tank, it is imperative that the "septic tank be pumped out periodically." Remember, sludge is not biodegradable. If it's not pumped out, sludge will accumulate until it overflows.

The frequency of pumping out will depend primarily on the amount of wastewater that goes through the system each day. The frequency also depends on how careful you are about not throwing excess fats, rinds and other similar garbage down the drains. The more solid waste thrown in the system, the quicker the tank will fill up. Heavy flows of water also tend to make the tank fill up more quickly. That is why it is best not to use a garbage disposal in the system when you have a septic tank, and why water should not be left running indiscriminately in sinks or toilets.

It is important to get the septic tank cleaned  before the sludge level gets high enough so that any of the solid material at the bottom, or the semi-solid scum at the top can flow out into the drainage field. This will quickly clog the drainage pipes and the soil into which they drain.

Make certain there is live bacteria in your system at all times. The bacteria's job is to digest all organic waste matter in the system. If there is no bacteria in your system it will simply act as a holding tank for your waste. It becomes full, and natural digestion will not occur. That is when the system backs up.

Bacteria are killed off or overrun because of:

• excessive quantities of detergents, laundry waste, bleach, household chemicals, and caustic drain openers.

• garbage disposal grinds which substantially increase the accumulation of solids.

• disposal of items not biodegradable in the system (plastics etc.).

• disposal of excessive amounts of grease and fats, which are biodegradable but need particular types of bacteria to digest them.

• disposal of cigarette butts and sanitary napkins which are also biodegradable but are not readily decomposable.

• too many people using a smaller/inadequate or failing system.

If you have no bacteria in your system and you add enzymes to the system, it simply will not help and your system will still not work. Enzymes are simply a catalyst for bacteria. If there is no bacteria in your system, why use enzymes?

From time to time, you should add "l00% Natural LIVE ADULT BACTERIA" to your system.

Do not add just any kind of bacteria. Call your septic professional. He can add adult live bacteria that are "FACULTATIVE," which will work with or without oxygen.

[Please refer back to where we told you that "Bacterial Action Goes On At The Bottom Of The Septic Tank."]

A facultative bacteria is one that would be useful in situations that have air and in situations where there is no air (anaerobic situations). The bottom of the septic tank has no oxygen and therefore needs anaerobic bacteria.

As communities grow more crowded and the awareness of the impact of one home upon another grows, regulatory authorities have begun to pay more attention to proper maintenance of each individual property.

One factor under scrutiny is the septic system. Rather than leave it up to the home owner to decide how often to clean and pump a system, a growing number of municipalities are imposing requirements. In addition, state laws are becoming more stringent. If an existing system fails, or in the building of new homes, some states have begun imposing tighter regulations on the types of systems allowed.

Nationwide about 25% of all homes rely on a septic system. With so many systems in constant use and most of them older models of inferior design, fear has been mounting that improperly maintained systems will pollute ground-water supplies or that the health of ones own family could be jeopardized.

On the local level, some individual communities are starting to enact regulations. Brookfield, CT, for example, passed an ordinance in 1985 requiring the inspection of every home with a septic system, once every four years.

On the state level, Connecticut passed legislation in 1989 requiring the replacement of any failed tank with a more sophisticated, more expensive two-compartment tank.

THE BEST WAY TO AVOID major repairs or replacement, or to avoid being fined for operating a substandard system is to call Williams & Bay Pumping Services.

• We can coach you on all local laws and regulations.

• We can check out your system.

• We can coach you on the proper maintenance of your system.

• We can supply you with commercial strength PRO-PUMP* and confirm the dosage rates needed to maintain your individual system.

• We can save you money by pumping out your system before it fails.

PLEASE NOTE...Your septic system does have potential health concerns for you and your family. Accidents due to noxious gases have occurred.

Septic System Treatment
Local & State Regulations
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