A septic tank collects wastewater from your toilets, tubs and washing machines. Solid waste settles at the bottom of the tank while fats and grease drift to the top.
The bacteria in your septic system release gases into the air through a vent in your septic tank’s lid. The gases are also absorbed into the soil of your drain field. Click https://www.septictankarmadale.com.au/ to learn more.
A septic system treats wastewater from toilets, sinks, bathtubs and laundry in homes that aren’t connected to a public sewer system. The process consists of a tank, an absorption field or seepage bed and piping that leads to the ground. The septic tank digests organic waste and separates the floatable materials, such as oils and grease, from the wastewater. The clarified liquid that remains is known as effluent.
Oils and solids settle to the bottom of the tank in a layer called sludge. Special compartments and the outlet prevent sludge from leaving with the wastewater. Effluent flows from the tank through a perforated pipe into a soil absorption system, commonly referred to as a drain field or leach field. The soil filters the effluent and the natural filtration process protects nearby groundwater and surface water from pathogenic bacteria.
The absorption field is a series of trenches or a seepage bed with gravel where wastewater seeps into the ground through a network of pipes. The pipes are placed in the ground at least six feet below the soil line and are typically constructed of polyethylene, fiberglass or clay. The pipe network in the absorption field must be properly sized and installed to ensure that it functions effectively.
Once the septic system is in place, the absorption field needs to be maintained by adding 8 to 12-inches of mulch around the septic tank, septic tank pipes and the absorption field to prevent erosion and aerate the soil. The mulch should be made from organic material, such as straw or hay, to reduce the risk of water and nutrient runoff into surface and groundwater.
Homeowners can help maintain their septic tank and system by following simple tips, such as using water-efficient appliances and fixtures. They should also limit the number of showers and washing machines used at one time to avoid overloading the system, and wash clothes over several days instead of back-to-back. Finally, it’s important to have a professional inspect the septic tank and conduct routine pumping. A licensed septic tank operator will also be able to provide the homeowner with a record of tank sludge levels and other important data that should be reviewed periodically.
Sludge
Septic tanks separate sewage into three distinct layers according to density differences. The top layer, the scum layer, consists of floating substances, mostly oils and greases that float above the water. Aerobic bacteria in the septic tank digest most of this layer. The middle layer, the wastewater layer, is composed of the liquid portion of sewage waste and solid particles that are smaller than a human hair. The bottom layer, the sludge layer, is dense and made of non-liquid waste materials that sink to the bottom of the septic tank. The sludge layer contains non-decomposable waste such as soil, grit, and unconsumed food particles.
A septic system has an inlet and outlet pipe that extend from the septic tank into your home. Each time you flush your toilet, hydraulic pressure pushes wastewater up through the inlet tee into and out of your septic tank and into the absorption field. The septic tank inlet and outlet tees are spaced below the scum and sludge layers so that these solids do not clog the tees or your absorption field.
In order to prevent septic tank sludge from building up, it is important to have the septic tank pumped periodically. When the septic tank is too full, solid waste that hasn’t decomposed discharges into the drain field, where it can clog leach field piping and reduce the soil porosity, thus decreasing the efficiency of the absorption system.
Using a septic tank treatment product will help to keep sludge levels down between septic tank cleanings. Bacterial additives add a healthy dose of hard-working bacteria to the septic tank that work hard to break down solid waste. This will keep sludge levels down and help extend the period of time between septic tank cleanings.
If you decide to use a septic tank treatment product, be careful not to pour the chemical additives directly onto the sludge layer. Doing so may throw the primordial ecosystem that’s developed over time in your septic tank out of whack, and disrupt the natural enzymes that are already breaking down the sludge sent to it.
Scum
Septic tanks are vital for households, but they must be maintained properly to work efficiently. If a septic tank is not properly maintained, it can lead to wastewater leaking out of the system and polluting groundwater. This can cause a variety of issues, from contamination to health problems for residents. Regular septic tank pumping is one of the best ways to ensure that the septic system works as it should.
The septic tank is designed with a scum layer at the top, a sludge layer at the bottom and a clear water zone in between. When a septic system is working correctly, the bacteria thriving in these layers perform a process called liquification. This process breaks down organic materials in the sludge and scum layers, which allows them to flow into the liquid waste that drains out of the septic tank.
A scum layer is composed of substances that are lighter than water, primarily fats and oils. These materials float on the surface of the wastewater in the septic tank and are digested by aerobic bacteria. Solid materials that are denser than water (such as soil, grit, bones, unconsumed food particles) sink to the bottom of the septic tank to form a thick layer of sludge. Anaerobic bacteria that thrive in this layer consume these solids, producing methane and other gases as they do so.
As the sludge and scum build up in the septic tank, their volume reduces the effective water volume in the clear space in between. If this happens, the septic tank may need to be pumped sooner than expected.
The sludge and scum layers can also block the septic tank outlet pipe. This can allow wastewater to leave the septic tank but not be separated from the solids. This can cause the solids to enter the drain field and clog pipes and gravel in the septic system, leading to expensive repairs or system replacement. Regular septic tank pumping helps prevent this from happening by ensuring that the solids and sludge are pumped out of the tank, leaving only the water behind in the effluent layer.
Effluent
When you flush your toilets, wastewater travels through a main drainage pipe to the septic tank. The septic tank is a concrete or plastic box that holds the wastewater until solid wastes have settled or dissolved. Heavy solids, like dirt and grit, sink to the bottom of the tank where they form a layer called sludge. Lighter solids, like oil and grease, float on top of the wastewater where they partially decompose. The clarified liquid in the space between these layers is called effluent.
The septic tank also contains an inlet baffle that forces the wastewater downward as it enters. This helps the solids to settle and dissolve faster. It also prevents wastewater from skimming across the surface and exiting the septic tank untreated.
Inside the septic tank, bacteria break down the organic wastes. This process creates gases, including hydrogen sulfide, which smells like rotten eggs. To keep these odors from entering your home, the septic system includes a vent pipe that extends through the lid of the septic tank. The vent is usually shaped like a mushroom and may have a charcoal filter to reduce odors.
If solid inorganic wastes enter your septic system, they can clog pipes and block the flow of wastewater. Keeping solid inorganic materials out of your septic system can help it work more effectively, and it can extend the time between septic tank pumping. Items that shouldn’t go down your drains include cigarette filters, diapers, tampons, paint cans, foil wrappers and condoms.
Once the septic tank has held the wastewater for a sufficient amount of time, a distribution box evenly distributes the effluent to a septic tank drain field or leach field. The effluent is piped to a shallow underground trench of clean gravel or stone.
The stone and gravel provide a filter to remove large solids from the effluent before it enters the soil. The effluent then percolates through the ground where microbes further treat it. Alternatively, a septic tank can also be connected to a drainfield made from black earth or gravel with a geofabric covering that filters the wastewater before it percolates through the soil.
