Your septic tank is designed to hold wastewater from the home for adequate time so microorganisms can decompose some of the waste. Heavy solids sink to the bottom of the tank while oils and fats float to the top. The clarified wastewater (effluent) is discharged into a soil absorption or leach field. Click the Visit Website to learn more.

Wastewater from homes flows through pipes into septic tanks buried underground. The tank provides a relatively quiet body of water that holds the wastewater long enough for solids to separate from it by both settling and flotation. Heavy solids settle to the bottom of the tank forming a layer of sludge, while oils and grease float to the top forming a layer of scum. Bacteria decompose the floating wastes. The liquid wastewater between these layers, called effluent, exits the tank through a pipe connected to a distribution box and perforated pipes that carry it to an absorption field (also known as a drain field or leach field).

The septic system is designed to break down organic waste, but some materials will still clog the pipes. If you notice sewage seepage into your home or yard, it is time to call for professional help. Other signs include gurgling in toilets and slow draining.

A septic tank should be inspected and pumped out on a regular basis by a licensed septic pumper to ensure it is operating properly. A tank that has reached its maximum capacity may start to overflow, which can cause sewage to back up into the house. It is also important to keep household products like paint, cleaning agents, dental floss, hygiene products and paper towels out of the septic system, as these can contribute to clogs and prevent wastewater from discharging properly.

The bacteria in a septic tank generate gases that must be vented to prevent a buildup of pressure that could stop or reverse the flow of wastewater from your home. The most common gas is hydrogen sulfide, which has a distinct odor similar to rotten eggs. The septic tank vent is usually a mushroom-shaped device that has a charcoal filter to reduce odors.

The wastewater leaves the septic tank through a perforated pipe connected to a distribution box, which evenly distributes the wastewater into a series of trenches in a drain field. The absorption field is partially filled with washed gravel or gravelless product that acts as a biological filter to purify the wastewater as it percolates into the soil.

Sludge

If you have a septic tank, at some point you’re going to have to deal with the sludge that forms in your tank. It may seem gross, but it’s a necessary part of septic tank maintenance. This is because your septic system depends on natural waste separation. It’s a little bit like the natural cycle of decomposition that occurs in our bodies, but on a much larger scale.

Essentially, a septic tank is a buried watertight container that holds wastewater long enough to let the solid waste settle. Oil and grease floats to the top in a layer known as scum, while soil, grit, bones, unconsumed food particles, and other organic matter sinks to the bottom forming sludge. Compartments and a T-shaped outlet prevent the sludge and scum from leaving your tank, but the clarified wastewater (effluent) that remains between the scum and sludge layers travels through the septic tank’s outlet into the drain field.

A septic tank is a complex system, and it takes time for all the organic waste to separate from wastewater. The more solids you put into your septic tank, the longer it will take for this process to complete. It’s also important that you don’t flush non-biodegradable waste items like cigarette butts, cotton buds/swabs, condoms, or menstrual hygiene products into your septic tank. These can clog pipes and cause problems for your septic tank and drain field.

When a septic tank is operating properly, beneficial bacteria residing in the sludge and scum layers break these materials down into smaller-sized substances. This liquefaction of solids happens thanks to the normal metabolic activities of these bacteria.

It’s important to keep your septic tank pumped on a regular basis. This helps to ensure that your septic tank can keep up with the volume of solids it’s storing. If you don’t pump your septic tank often enough, the sludge layer will start to fill up and reduce your septic tank’s effective volume.

If the sludge layer covers too much of your septic tank, it will stop wastewater from reaching the drain field and allow sewage to back up into your home. This can also cause pathogenic bacteria and dissolved organic pollution to seep into the environment.

Scum

The septic tank should normally have a scum layer floating on the top of the wastewater. This scum layer is primarily made of fats, oils and greases (FOG’s) that have been flushed down the drain. It may also contain other lighter discharged material such as soap scum and food particles. This layer is a clear, greenish or greyish bubbly liquid. It is not uncommon to see the odd floater or bit of paper rising up through this layer as well.

When a septic system is working as it should, beneficial bacteria work to digest the organic materials in these three separate layers of the septic tank. This activity causes the scum and sludge layers to break down and eventually be taken into the wastewater layer as a slurry of very small organic materials.

The sludge layer is the bottom of the septic tank and contains human waste, other solid waste materials, and the remains of dead bacteria. This layer can become problematic if it is allowed to build up too thickly. This can block the inlet pipe and disrupt flow to the septic system drain field.

To avoid this, it is a good idea to use septic tank treatment products regularly. These can help to reduce the amount of sludge that builds up in the tank over time. During this process, the bacteria in these products can raise the total plate count and cause the sludge and scum layers to break down faster. This can reduce the frequency of septic tank pumpouts and keep the septic system running smoothly.

A septic tank is only as effective as the bacteria that live inside of it. This bacterial community needs to be healthy in order to perform its job effectively. Chemical additions that impact the microbial community should be kept to a minimum, including household cleaners, detergents and other chemicals. If the septic tank has too much sludge or scum it can become difficult for bacteria to digest it, which can lead to problems with the septic system.

Drain Field

When liquid wastewater flows through your septic system, it leaves through a series of pipes to a septic tank drain field. The drain field is a shallow area of uncovered soil that filters untreated wastewater as it percolates through rocks, dirt and sand. The bacteria, viruses, and excess nutrients are naturally removed from the water before it returns to underground aquifers. A well-functioning septic system requires proper design, installation and maintenance. If you notice a foul smell, wet or soggy spot over the drain field or slow-to-drain bathroom or kitchen sinks, these are signs that something is wrong with your septic system, and you should contact a licensed plumber to investigate.

Solid waste deposits into your septic tank in three forms: sludge, scum and liquid (effluent) wastewater. Over time, sludge material settles to the bottom of your septic tank, while fats, oils and grease float to the top as scum. Anaerobic bacteria inside your septic tank feed on these organic wastewater pollutants. Over time, these bacteria break down the sludge and scum until they can be pumped out of the tank. Liquid effluent exits the septic tank through an inlet baffle and out of your home through a pipe to your septic system drain field.

A septic tank and drain field are designed to work together to treat household wastewater in an environmentally friendly way. Having a properly sized and located drain field ensures that effluent wastewater is efficiently absorbed into the surrounding soil without overloading it, which could cause the absorption field to clog and fail. To prevent these problems, have your septic system inspected and pumped on a regular basis, and follow basic maintenance tips.

These include limiting the amount of water you use to avoid overfilling your septic tank and drain field, and using low-flush toilets. You should also avoid driving or parking vehicles or equipment over your septic system and refrain from building structures over the absorption field. These actions can crush the pipes within your drain field and interfere with the microbiological process that breaks down the waste.