How Septic Tanks Work

Knowing how septic tanks work can be the difference can be helpful as it can prevent a small issue from becoming a major one, especially when it comes to waste water.

From the occasional toilet clog to a full-blown sewage backup, septic tanks can mean the difference between a minor inconvenience and an expensive plumbing nightmare.

In this article, we explain what is a septic tank and also how they work so that you can have a greater knowledge of what’s happening.

Understanding the ins and outs of these subterranean systems can help homeowners keep their septic tanks in check, preventing costly breakdowns and keeping your home running smoothly.

Let’s take a closer look at how septic tanks work.

Definition of a Septic Tank

A septic tank is an underground system designed to treat wastewater and solid waste from a home or business.

There are different types of septic tank, but they are typically made of concrete, fibreglass, or plastic and all modern septic tanks are divided into three layers.

  • The top layer is the layer of scum, where heavier solids like grease and oils float to the top.
  • The middle layer consists of liquid wastewater,
  • The bottom layer holds heavier solids such as sand, gravel and silt.

Wastewater enters the tank through an inlet pipe and flows out through an outlet pipe (organic waste).

Septic tanks are usually connected to a drainage field where treated wastewater can be safely released back into the environment.

Septic systems have been used for centuries as an alternative to public sewer systems in rural areas or places with poor infrastructure.

Today, septic tanks are still widely used for treating domestic sewage from homes and businesses that don’t have access to a public sewer system.

As wastewater flows through a septic tank, bacteria break down organic matter and separate out lighter solids from heavy solids.

Aerobic bacteria break down organic matter in the presence of oxygen while anaerobic bacteria do their work without it.

After passing through the septic tank, liquid waste travels via perforated pipes to a drain field where it is filtered naturally by the soil before being released into the environment.

Untreated waste is of course bad for the environment releasing harmful bacteria which becomes a health hazard.  This is why it’s also important to understand the ground surface and ground conditions around the tank for both domestic properties and commercial properties.

A Quick Overview of How Septic Tanks Work

how a septic tank works - a diagram

Septic tanks are an efficient and cost-effective method for treating wastewater from homes and businesses, especially in areas where there isn’t access to a public sewer system.

The general process of how a septic tank works can be summarized as follows:

  • Wastewater enters the tank through an inlet pipe and is divided into three layers.
  • The top layer collects scum, the middle layer holds liquid wastewater, and the bottom layer contains heavier solids such as sand, gravel and silt.
  • Bacteria then break down organic matter, separating out lighter solids from heavy solids.

After passing through the septic tank, liquid waste travels via perforated pipes to a drainage field where it is filtered naturally by the soil before being released into the environment.

Septic tanks are easy to maintain but should be checked regularly to ensure they are functioning properly. Regular inspections also help detect any potential problems before they become serious issues.

Components of a Septic System

A septic system is composed of a variety of components that work together to treat wastewater from homes and businesses. The main components are the underground tank, outlet pipe, drain field and effluent filter.

The tank is where all the wastewater enters and is divided into three layers: solids, scum and liquid. Aerobic bacteria break down the organic matter in the tank, separating out lighter solids from heavier ones.

The liquid waste then passes through an outlet pipe to a drain field, where it is filtered naturally by the soil before being released into the environment.

An effluent filter helps to ensure that any remaining solid particles are removed before the water reaches its final destination.

Septic systems can be a great solution for properties located in areas with no public sewer system – you just make sure you keep it maintained.

Inlet and Outlet Pipes

Inlet and outlet pipes are essential components of a septic tank system.

The inlet pipe is the pipe that carries domestic sewage from the house to the septic tank.

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It’s important to make sure this pipe is installed correctly, as it needs to be able to withstand high pressures and temperatures.

The outlet pipe is equally as important, as it carries liquid wastewater away from the septic tank and into a drainage field or sewage treatment plant.

This pipe should be made of durable materials such as PVC or ABS plastic since it needs to be able to handle heavy solids like waste particles while still allowing liquid wastewater to pass through freely.

Both inlet and outlet pipes need regular maintenance in order to ensure they are functioning effectively and safely – so remember to check them regularly!

Underground Tank

definition of a septic tank underground tank

An underground tank is a key element in any septic system. This tank is typically buried at least two feet below the ground and stores all the solid waste, including human waste, kitchen scraps, and other organic matter.

The waste is broken down by aerobic bacteria in the tank and separated into three layers: a scum layer that floats to the top, a middle layer of wastewater, and a bottom layer of sludge.

The wastewater from the middle layer then passes through perforated pipes to the drain field or sewage treatment plant where it is further processed.

It’s important to have an underground tank installed correctly so that it can function properly and safely for many years – if not taken care of properly, it can cause serious environmental issues.

Regular maintenance and inspections are also essential for keeping your septic system healthy!

Drainage Field or Drainfield

The drainage field, also known as the leach field or soakaway, is a vital part of any septic system. This area is typically located away from the house and receives liquid wastewater from the septic tank via a drainage pipe.

The liquid waste then percolates through the soil in the drainage field, allowing it to be naturally filtered. The soil acts as a natural filter and absorbs impurities such as heavy solids, lighter solids and dissolved particles.

As this process takes place, anaerobic bacteria break down the organic matter in the wastewater before it returns to groundwater or public sewer systems.

It’s important to ensure that your drainage field is functioning properly so that it can continue to safely and effectively process domestic sewage – if not taken care of properly, it can cause serious environmental issues.

Effluent Filter

Effluent filters are an important part of a septic system and play a vital role in the proper functioning of your wastewater treatment.

These filters are typically installed at the outlet pipe of the septic tank and prevent any large solid waste particles from entering the drain field.

The effluent filter collects all the solid waste particles, including grease, oils, soaps and other contaminants, before it passes through to the drainage field.

Not only do these filters help keep your system running smoothly, but they also help protect local water sources from contamination by preventing solids or scum from entering groundwater.

To ensure that your effluent filter is performing as expected, it is important to regularly inspect and clean it if necessary. It is also recommended that you replace your filter every 2-3 years for optimal performance.

With regular maintenance and care, an effluent filter can be an effective tool in keeping your septic system running efficiently and protecting local water sources from pollution.

The Three Layers in the Septic Tank

layers in a septic tank

Septic tanks are an essential component of the septic system, and understanding how they work can help ensure that your wastewater treatment is running as efficiently as possible.

A typical septic tank is composed of three layers: a scum layer, a middle layer, and a sludge layer. The scum layer is the topmost part of the tank and consists of all the lighter solids, such as oils and soaps from domestic sewage.

This layer floats to the top before being released into the drain field through an outlet pipe.

The middle section of the tank contains both liquid waste and organic matter that has been broken down by aerobic bacteria. This layer acts as a buffer between the heavier solids in the sludge layer below it.

At the bottom lies the sludge layer which contains heavy solid wastes like human excrement, paper products, and other materials that have not yet been broken down by bacteria.

These solids are slowly digested by anaerobic bacteria before being discharged through perforated pipes or an effluent filter into a drainage ditch or public sewer.

By understanding how these three layers work together to process wastewater within your septic system, you can ensure that your wastewater treatment is functioning optimally at all times!

Scum Layer

The scum layer is the topmost part of your septic tank. This layer contains all the lighter solids, such as oils and soaps from domestic sewage.

It forms a floating barrier between the heavier sludge layer below and the middle section of the tank. The scum layer floats to the top before being released into the drain field through an outlet pipe.

To keep your septic system working optimally, it’s important to remember that this scum layer must be emptied periodically.

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If it’s not, it can clog up your system and prevent liquid waste and organic matter from entering your drainage field.

To avoid this, you should have your septic tank pumped regularly to ensure that all layers are balanced appropriately and functioning effectively.

By understanding how each component of your septic system works together, you can ensure that your wastewater treatment is running smoothly at all times!

Middle Layer

The middle layer of your septic tank is where the majority of waste particles and liquid wastewater settle. This layer contains both aerobic bacteria, which break down organic matter, as well as anaerobic bacteria, which convert solids into a liquid form.

As this middle layer is constantly in motion due to the incoming flow of wastewater from the inlet pipe and outgoing flow from the drainage pipe, it’s important that there is enough space for all of these processes to take place without any obstruction.

This middle layer also serves as a barrier between the lighter scum layer above and the heavier sludge layer below.

By separating these two layers, you can ensure that heavy solids don’t get trapped in your drain field, while simultaneously allowing for efficient treatment of your wastewater.

By understanding how each component of your septic system works together, you can keep your septic tank running effectively and make sure that your sewage treatment plants have access to a clean effluent filter by properly maintaining your underground tank!

Sludge Layer

The bottom layer of your septic tank is referred to as the sludge layer. This layer consists of the heaviest materials, such as oils and grease, that settle at the bottom.

If not maintained properly, this layer can become clogged and block up your entire system. It’s important to regularly check on the sludge level in your tank in order to make sure it doesn’t become too high.

If you notice that the sludge level is higher than normal, it’s time to call a septic system professional for help. They will be able to inspect your tank and determine whether or not you need a complete septic tank cleaning or pump-out.

This process involves pumping out all of the wastewater from your tank and removing any accumulated solids so that your system can operate effectively again.

It’s also important to remember that regular maintenance is key when it comes to keeping your septic system working properly.

By monitoring the levels of solid material in your tank and scheduling regular cleanings or pump-outs, you can ensure that everything runs smoothly and avoid costly repairs down the line!

Types of Bacteria Used in a Septic System

septic tank bacteria

Septic systems rely on bacteria to break down organic matter and convert it into liquid wastewater. There are two main types of bacteria used in septic systems- aerobic and anaerobic.

Aerobic bacteria need oxygen to survive, while anaerobic bacteria do not. The type of bacteria used in a septic system will depend on the size of the tank, the amount of wastewater produced, and other factors.

Aerobic bacteria are most commonly found in small septic tanks because they require less oxygen than anaerobic bacteria.

These helpful organisms break down organic matter quickly and efficiently, resulting in cleaner wastewater that can be safely discharged into the environment.

Anaerobic bacteria are typically used for larger tanks or those that produce more wastewater. This type of bacteria is slower-acting than aerobic bacteria but can still break down organic matter with time.

They also help reduce odours from your tank by consuming excess nitrogen and converting it into harmless nitrogen gas.

No matter which type you choose for your septic system, it’s important to keep up with regular maintenance to ensure that your tank is functioning properly.

Keeping an eye on levels of sludge and performing regular pump-outs or cleanings can go a long way towards keeping your septic system running smoothly!

Aerobic Bacteria

Aerobic bacteria are essential for any septic system, and they can be a huge help when it comes to keeping your tank clean.

These helpful organisms require oxygen to survive, and in smaller tanks, they break down organic matter quickly and efficiently. This helps keep the wastewater clean and safe for discharge into the environment.

These friendly bacteria also help reduce odours from your tank by consuming excess nitrogen and converting it into harmless nitrogen gas.

While aerobic bacteria act faster than anaerobic bacteria, they do need regular maintenance to ensure that they’re functioning properly.

Checking sludge levels and performing regular pump-outs or cleanings can go a long way towards keeping your septic system running smoothly!

If you’re looking for a way to keep your septic system working its best, aerobic bacteria might be just what you need.

With proper maintenance, these helpful organisms will keep your tank clean and odour-free while ensuring that wastewater is safely discharged into the environment.

Anaerobic Bacteria

Anaerobic bacteria are not as well-known as their aerobic counterparts, but they play an important role in septic systems! These helpful organisms can be found in the middle layer of a septic tank, where they break down heavier solids and solid waste particles.

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The bacteria consume organic matter without needing oxygen to survive, and they help keep the wastewater clean and safe for discharge into the environment.

Septic systems rely on anaerobic bacteria to break down solid wastes that would otherwise remain in the tank. They also help reduce the amount of nitrogen released into the environment by breaking it down into harmless nitrogen gas.

In order for anaerobic bacteria to do their job properly, your septic system needs regular maintenance. This includes checking sludge levels, performing pump-outs or cleanings at least once a year, and adding bacterial additives when needed.

By keeping your tank clean and well-maintained, you’ll ensure that your septic system is functioning optimally!

If you’re looking for a way to keep your septic system running smoothly, consider giving anaerobic bacteria a try!

With proper maintenance and regular cleaning, these helpful organisms will help break down heavy solids and waste particles while keeping your tank odour-free and safe for discharge into the environment.

Maintenance Tips for a Septic System

septic tank maintenance tips

Proper maintenance of your septic system is key to keeping it running smoothly and safely.

Here are some tips for ensuring that your septic tank remains in top condition:

• Monitor your sludge levels regularly, as this will help you determine when it’s time for a pump-out or cleaning. Pumping out and cleaning the tank at least once a year is recommended, even if the sludge levels seem low.

• Add bacterial additives to the tank periodically to help keep the anaerobic bacteria active. These additives can be purchased from most home improvement stores.

• Avoid putting harsh chemicals or cleaners into your septic system, as they can damage the bacterial cultures that keep waste particles broken down. Additionally, refrain from planting trees or shrubs near the drainage field, as their roots may compromise the integrity of your system.

• Check all pipes and connections regularly for signs of leakage or clogging. If you notice any issues with these components, contact a professional plumber right away so they can assess and repair them quickly before further damage is done.

By following these simple maintenance tips, you can keep your septic system running smoothly and safely for years to come!

Regular Inspections and Pump-Outs

Regular maintenance, such as inspections and pump-outs, is crucial for ensuring the optimal functioning of your septic system.

Regular inspections by a professional plumber on a regular basis will help identify any potential problems before they become more serious, such as clogged pipes or broken connections.

Regular pump-outs of the tank are important as they remove solids and water waste that have accumulated over time and can cause blockages in your system.

Pump-outs should be done at least once a year, or every two years depending on the size of your tank and usage levels.

During a pump-out, all of the liquids and heavy solids are removed from the tank, leaving only lighter solids which will eventually decompose and be released through the outlet pipe into the drain field. This process helps ensure that your septic system is able to operate properly.

It’s also important to remember that regular maintenance isn’t just about pump-outs – it’s also about making sure that all components and network of pipes are working properly and that there aren’t any signs of leakage or clogs in your pipes and connections.  At the same time, you can also check for poor drainage too.

Avoiding Certain Chemicals and Substances

Many homeowners are not aware of the potential damage that certain chemicals and substances can cause to their septic system.

It’s important to avoid putting items such as motor oil, paints, solvents, pesticides, and other harsh chemicals down the drain or toilet as they can all have a negative effect on your septic tank and system.

Additionally, paper towels, cigarette butts, coffee grounds, feminine hygiene products, diapers and many other non-biodegradable materials should also never be flushed down the toilet as these can clog pipes or create an imbalance in your tank.

Whenever possible, try to use biodegradable soaps and detergents for cleaning around the house as these will break down more quickly in your tank.

Additionally, limit hot water usage when washing dishes or clothes as this will reduce the amount of wastewater coming into your tank which will help it process more efficiently.

Finally, if you need to dispose of any hazardous waste like motor oil or paint thinners then it’s best to take them to a local recycling centre where they can be disposed of safely.

Factors That Can Affect the Functioning of a Septic System

facts which impact septic tank functionality

Septic systems are an essential part of many homes, but they can be affected by different factors. One of the main factors that can impede a septic system’s functioning is too many solids in the tank.

If you flush items such as paper towels, feminine hygiene products and diapers down the toilet, these will not be able to break down and could clog up the pipes or create an imbalance in your tank.

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Harsh chemicals like motor oil, paints and solvents should never be poured into septic tanks as these can cause serious damage.

It’s also important to limit hot water usage when possible as this will reduce the amount of wastewater that comes into your tank which can help it operate more efficiently.

If you’re using biodegradable soaps and detergents for cleaning around the house, make sure they’re compatible with septic systems otherwise they may not break down fast enough which could lead to problems with your system.

By following these simple tips, you can help ensure that your septic system operates properly for many years to come.

Groundwater Levels and Soil Type

Groundwater levels and soil type are two key factors that can influence the performance of a septic system. The soil surrounding your septic tank must be able to absorb liquid waste and allow it to move away from the tank into a drainage field, otherwise, it could cause leaking or flooding around your property.

Additionally, the groundwater level needs to be low enough so that wastewater can flow freely away from your tank.

If the groundwater level is too high, then the wastewater won’t be able to escape and could back up into your home or yard.

It’s important for homeowners with septic systems to have their soil type tested on an annual basis and make sure their tank is located far enough away from any water sources such as wells, rivers or lakes.

Additionally, if you notice any changes in your system such as slow-draining toilets, pungent odours or standing water near your home, these could all be signs that there’s an issue with either your soil type or groundwater levels so you should contact a professional right away for help.

Proximity to Trees, Vegetation, or Other Structures

When it comes to keeping your septic system running smoothly, it’s important to remember that the location of your tank is key. You should make sure that your tank is at least 10 feet away from any trees, vegetation, or other structures such as a shed or garage in order to ensure proper function.

Trees and other plants have roots that can penetrate pipes and cause blockages which can lead to backed-up sewage and flooding, while nearby structures could potentially crush the pipes leading into and out of your septic tank.

Additionally, you want to be sure not to plant anything directly over or near your drain field as this could interfere with the soil’s ability to absorb liquids properly.

If you are unsure about what type of vegetation or structures are okay for proximity to your septic system, contact a professional for help so they can assess the situation and provide advice on what’s best for you.

FAQs

Here are some common questions relating to how septic tanks work:

What do I need to know about septic systems?

Septic systems are an alternative to sewer systems for managing and treating wastewater from households and buildings. They are commonly used in rural or remote areas where centralized sewer systems are not available. Here are some key points you need to know about septic systems:

  • Components: Septic systems generally consist of two main components: a septic tank and a drain field (also known as a leach field or soil absorption field). Wastewater from your home is sent to the septic tank, where solids and liquids are separated. The solids settle to the bottom, forming a sludge layer, while the fats, oils, and grease float to the top, creating a scum layer. The remaining liquid in the middle is called effluent.
  • Treatment process: The septic tank serves as a primary treatment, where bacteria break down the solid waste into simpler compounds. The effluent then flows to the drain field, where it is further treated as it percolates through the soil. The soil acts as a natural filter, removing pathogens, nutrients, and other contaminants before the treated water reaches groundwater or nearby surface water.
  • Maintenance: Regular maintenance is essential for the proper functioning of a septic system. This includes pumping the septic tank every 3-5 years, depending on usage, to remove the accumulated sludge and scum. Inspecting the system regularly (at least once a year) for any signs of damage or malfunction is also necessary.
  • Signs of trouble: Indications that your septic system may not be working properly include sewage odours, slow drains, gurgling noises in the plumbing, standing water or lush vegetation over the drain field, or sewage backups. If you notice any of these signs, contact a professional to assess and repair the system.
  • Do’s and don’ts: To keep your septic system functioning optimally, avoid flushing non-biodegradable items such as wipes, diapers, and feminine hygiene products. Limit the use of harsh chemicals, as they can kill beneficial bacteria in the tank. Be mindful of water usage to prevent overloading the system. Avoid planting trees or large shrubs near the drain field, as their roots can damage the pipes.
  • Regulations: Septic systems are subject to local and state regulations, which may dictate design requirements, permits, inspections, and setbacks from property lines, wells, or water bodies. Always consult with your local health department or regulatory agency for specific requirements in your area.
  • Environmental concerns: When functioning properly, septic systems can effectively treat wastewater and protect public health and the environment. However, failing systems can contribute to groundwater contamination, surface water pollution, and the spread of waterborne diseases. Regular maintenance and proper use are essential to minimize these risks.
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Are Septic Tank Treatments Necessary?

Septic tank treatments, also known as septic tank additives, are products that claim to enhance the performance of your septic system by boosting the bacterial population or breaking down solid waste more effectively. These treatments typically contain bacteria, enzymes, or chemicals.

Whether or not septic tank treatments are necessary is a matter of debate. In most cases, a properly designed, installed, and maintained septic system should function efficiently without the need for additives. Septic tanks naturally contain a diverse community of bacteria that break down organic waste, and these bacteria can self-replenish as long as the system is not overloaded or exposed to harmful chemicals.

That being said, there are some situations where septic tank treatments might be considered, such as:

  1. After pumping the septic tank: Some people choose to add a bacterial treatment after the tank has been pumped to help replenish the bacteria population. However, this is usually not necessary, as bacteria from wastewater will repopulate the tank soon after pumping.
  2. Temporary relief: In certain cases, enzyme-based treatments may provide short-term relief from issues like slow drains or odours. However, these treatments should not be seen as a substitute for regular maintenance or addressing the underlying cause of the problem.

It is important to note that some chemical-based septic tank treatments can be harmful to the septic system, as they can kill the beneficial bacteria or disrupt the natural balance in the tank. Additionally, some additives may not be approved for use in certain jurisdictions, so it is essential to check local regulations before using any septic tank treatments.

Ultimately, the key to a healthy septic system is proper design, installation, maintenance (including regular pumping), and responsible use. Relying on septic tank treatments as a substitute for these practices is not recommended. If you are experiencing problems with your septic system, consult a professional to diagnose and address the issue.

Why Do Septic Tanks Back Up?

Septic tanks can back up for a variety of reasons, often indicating an issue with the septic system.

Here are some common causes of septic tank backups:

  1. Full septic tank: If the septic tank is not pumped regularly, sludge and scum layers can accumulate, eventually reducing the tank’s capacity and causing wastewater to back up into the house. Regular pumping (every 3-5 years, depending on usage) is essential to prevent this issue.
  2. Clogged inlet or outlet pipes: If the pipe connecting your home to the septic tank (inlet pipe) or the pipe connecting the tank to the drain field (outlet pipe) becomes clogged or blocked with debris, wastewater cannot flow properly and may back up.
  3. Drain field failure: If the drain field becomes saturated or clogged due to excessive water usage, poor drainage, or a build-up of solids, the effluent cannot percolate through the soil, causing the wastewater to back up into the septic tank and potentially your home.
  4. Soil compaction or root intrusion: Compacted soil or invasive roots from trees and shrubs can obstruct the flow of effluent in the drain field, leading to backups.
  5. Improper system design or installation: If the septic system is not designed or installed correctly, it may not function as intended, resulting in backups. This can include issues such as inadequate tank size or improperly graded drain field.
  6. High water table: If the water table is too high, it can interfere with the proper functioning of the drain field, causing wastewater to back up.
  7. Heavy rain or flooding: Excessive rainfall or flooding can saturate the soil around the drain field, making it difficult for the effluent to percolate, leading to a backup.

To prevent septic tank backups, ensure regular maintenance, including pumping and inspection, is carried out. Monitor your water usage and be mindful of what goes down your drains, avoiding non-biodegradable materials and excessive use of chemicals. If you experience a septic tank backup, contact a septic system professional to assess and resolve the issue.

Summary

Here are the key takeaways from this article:

  • Understanding how septic tanks work is important in preventing costly breakdowns and potential health hazards.
  • Septic tanks are underground systems designed to treat wastewater and solid waste from homes and businesses, and they are still widely used in areas without access to public sewer systems.
  • The general process of how a septic tank works involve separating the waste into three layers, breaking down organic matter with bacteria, and filtering liquid waste through perforated pipes and soil before releasing it into the environment.

If you require septic tank maintenance or a septic tank installation, then Septic Tanks North West are readily available to assist you with over 20 years of experience in the industry.

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Updated: April 18, 2023

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