How a Septic Tank Works

Septic Tank Armadale is a buried, watertight container that traps gray and black wastewater from the home. Solid waste sinks to the bottom, forming sludge, while oils and grease float on top and form scum. Bacteria break down the contaminants and the liquid wastewater (effluent) leaves the septic tank through a pipe into the drain field.

Septic Tank

Wastewater enters a septic tank through an inlet pipe and settles, the heavier solids sinking to form a layer of sludge at the bottom. The lighter wastewater particles, oils, and grease float to the top. Bacteria inside the septic tank break down this solid material so that the wastewater can separate further and drain away easily. This is known as anaerobic digestion.

The septic tank is generally made from brick or concrete and can be built on-site or pre-fabricated in concrete rings, fibreglass or PVC. It has a lid to prevent unauthorized access and is usually covered with gravel in the garden to minimise visual impact. The tank is a primary treatment system for domestic grey or blackwater – it reduces the suspended solids in the wastewater.

The wastewater in the septic tank contains contaminants like human faeces, chemicals and bacteria which can cause disease and pollution to soil, waterways and water bodies. It also contains gases such as hydrogen sulfide which has the unpleasant odour of rotten eggs. The odour is generated when the bacteria break down these waste contaminants and is released through a vent pipe in the roof of the septic tank. The gasses are pumped out through the septic tank outlet to avoid build up of pressure that could stop or reverse the flow of the wastewater.

After the septic tank the liquid effluent flows into a soil absorption system, commonly called a drain field (alternatively referred to as a leachfield, percolation area or seepage bed). The drainfield is laid out in a series of trenches with gravel at specific depth and spacing. It is connected to the septic tank by perforated pipes. The drain field disperses the septic tank effluent into the ground where the gravel and soil naturally purifies it further.

A drainfield is designed to provide a long-term solution to the treatment of wastewater and disposal of septic tank effluent. This system is environmentally preferable to a conventional sewer system. However, it is still a wastewater treatment system that requires regular maintenance and pumping to ensure it works effectively.

Once the solid waste has settled and floatable matter has separated from the wastewater, it is pumped out of the septic tank into a field known as a drainfield or leach field. The septic system’s final treatment process takes place here, where water percolates through soil, further filtering and treating it for the environment.

During this time, the soil absorbs the water and removes harmful impurities, such as bacteria, viruses and excessive nutrients. The wastewater is then returned to groundwater.

The drain field is usually comprised of a series of pipes buried in a gravel-filled trench or chambers in the ground. As the wastewater trickles through the soil, it naturally filters out forms of nitrogen and phosphorous that could potentially harm the environment.

In addition to these natural processes, the drain field also benefits from healthy microorganisms that help break down and treat wastewater. However, if harmful chemicals, detergents or medicines are flushed into the septic system, these substances can kill these helpful microorganisms. This disrupts the normal wastewater treatment process and may cause a shutdown of the drain field.

Signs of a septic tank drain field problem include slow drainage or sewage backup in sinks and toilets. Additionally, a foul smell around the home and lush green patches over the drain field can indicate that roots have infiltrated the pipes. Items that should not be poured down a drain, such as fats, oils and grease (FOGs), can also clog pipes.

While a properly installed septic tank and drain field can last 20 to 30 years, the lifespan of your septic system is greatly dependent on how often you maintain it. A septic system that is regularly inspected, cleaned and pumped will prevent the formation of sludge and overflowing, which can lead to expensive repair and replacement costs.

Keep in mind that a septic tank and drain field can only operate in a well-draining soil. It is best to add 8 to 12-inches of organic material, such as leaves or straw, over the drain field and surrounding area. In order to avoid compaction and protect the soil, do not cover your drain field with driveways, parking areas or sheds. During the winter, freezing temperatures can also interfere with your septic system’s performance. If you notice your septic tank and/or pipes freeze, run water to thaw them. Adding mulch to your septic tank, pipes and drain field is also an effective way to insulate them against frost.

Designed to hold the wastewater from one household, septic tanks are buried and sealed water-tight. Wastewater enters the tank through an inlet pipe and travels to the first chamber. There, solids settle and scum (oil and grease) float to the top. The wastewater is then degraded anaerobically by bacteria without oxygen. This process removes up to 50 percent of the solid matter from the wastewater. The resulting effluent then flows out of the tank through a drain field that disperses it into soil.

When wastewater leaves your home, it contains dissolved contaminants such as disease-causing pathogens, phosphorous and nitrogen, and other organic matter. It also contains noxious gases such as hydrogen sulfide that are produced by the bacteria breaking down these materials. To prevent the build-up of pressure that could block or reverse the flow of wastewater, septic systems must be vented. These vents are usually located on the roof of the septic tank and are connected to a pipe that leads back through your plumbing system.

The septic tank includes compartments to separate the different layers of waste and debris. The bottom layer is sludge that sinks and the middle layer is liquid wastewater known as “effluent.” The water exits through the tank’s outlet into the drain field area where it is slowly dispersed into soil.

A septic tank must be large enough to accommodate the number of people using the system and to allow for periodic de-sludging. It must also be sized to accommodate the volume of solid matter that is expected to be generated each year, as well as the rate at which waste is deposited into it.

A septic tank can be built on site, or prefabricated tanks can be used. These tanks are buried underground, and are made of concrete, fiberglass or polyethylene. Some tanks are insulated to reduce heating costs and help conserve fuel. They also have a cover to keep the contents from contaminating the ground surface and to prevent birds and other animals from entering. The system should be inspected periodically to ensure that it is functioning properly.

If you’re a homeowner with a septic tank system, it’s important to keep up with regular maintenance. It is recommended to have your septic tank pumped every three to five years. This prevents the sludge and scum layers from rising too high, which can block and clog the septic tank system.

Wastewater from your toilets (called blackwater) and showers, bathtubs, sinks, washing machines and dishwashers (called greywater) runs into the septic tank through a main drainage pipe. Solid materials sink to the bottom of the septic tank and form a layer known as sludge, while oils, greases and other floatable substances rise to the top and form a layer called scum. Anaerobic bacteria in the septic tank digest these organic wastewater pollutants. Liquids flow out of the septic tank through an effluent filter and into your drain field, or leach field. The liquid then seeps into the ground through a series of perforated pipes buried in the drain field.

The soil in the drain field naturally filters and purifies the liquids before they reach groundwater. Maintaining a healthy septic tank and drain field helps reduce the risk of contamination in waterways and bodies of water, and it also protects local wildlife and ecosystems.

You can help by avoiding flushing non-biodegradable items down the toilet such as cigarette butts, cotton buds/swabs and menstrual hygiene products and condoms. These can clog and cause the septic tank to fill up more quickly. You can also help by conserving water and minimizing your household’s water usage, and by fixing any leaky faucets or fixtures.

Leaks and clogged toilets can waste as much as 70 gallons of water a day, which is enough to flood a home and cause serious structural damage. If you notice a wet spot on the lawn or if your toilets are running continuously, you have a leak in your septic system and need to call a septic service professional immediately.

It’s a good idea to map out the location of your septic tank and other system components with a diagram or use permanent stakes on the property. This will help you avoid damaging the septic tank and other system components when performing yard work or parking vehicles over them. You should also keep trees and other deep-rooted plants and shrubs away from the septic tank and drain field, to prevent their roots from growing into and clogging pipes.