Your home’s plumbing converges into the septic tank, where liquid waste pumps into a buried drain field. Solids sink to the bottom of the tank, while grease and other lightweight materials float to the top in a scum layer.
Bacteria break down sludge into a liquid called effluent. Then, bacteria in your soil treat it. Contact Septic Tank Armadale now!
All wastewater from your home flows through one main drainage pipe to the septic tank. The tank is a large, watertight container made of concrete, fiberglass, or high-density polyethylene. It is buried underground and has one end connected to the inlet wastewater pipe from your house and the other connected to a septic drain field (also known as a leach field).
Once in the septic tank, bacteria break down some waste materials. Heavy solids sink to the bottom of the tank, forming a sludge. Lighter solids, such as oil and grease, float to the top of the tank, creating a layer of scum. The liquid wastewater, called effluent, exits the tank through a T-shaped outlet. Compartments in the tank help prevent sludge and scum from leaving through the outlet, which should have a screen or filter to block large particles.
Bacteria also produce gases as they decompose waste. These gases, including hydrogen sulfide, which smells like rotten eggs, must be vented to the outside. They are released through a vent in the lid of the septic tank that usually has a mushroom shape and may be fitted with a charcoal filter to reduce odors.
A septic tank should be sized to hold enough of the waste material that it will not need to be pumped out frequently. This depends on the size of the household, water use, and habits, such as using the garbage disposal often, flushing paper towels down toilets, overfilling washing machines and dryers, dumping in hazardous chemicals or heavy detergent usage, which depletes the bacteria in the septic system.
The partially treated wastewater leaves the septic tank through a distribution box and perforated pipes to an absorption field, which is a series of trenches or beds that extend from the soil surface. The length and depth of the absorption field varies, depending on the size of the house. The distribution box evenly distributes the wastewater into all the trenches to avoid overloading any one part of the field. The soil in the drain field slowly dissolves the septic tank wastewater into the ground.
The Drain Field
A drain field, or leach field, receives liquid waste from the tank’s outlet pipe and disperses it into the soil. It includes downward-sloped underground pipes and gravel to ensure wastewater doesn’t reach the surface of your yard.
Everything deposited into the septic tank eventually becomes liquid (known as effluent) waste and exits the system through the drainfield. Solid waste can clog the drainfield, preventing it from working as intended. This is because the septic tank is designed to capture and hold the majority of the solid waste. Solids are broken down by bacteria inside the tank, and only the resulting liquid is sent to the drainfield.
Over time, sludge and scum build up in the septic tank. If the septic tank isn’t pumped frequently enough, this can lead to a reduced volume of liquid waste and a lessened capacity for effective separation of solid waste. Solids can then pass with the effluent into the drainfield, where they clog the lines and contaminate the soil.
The most common drainfield design is a gravel/stone one, where wastewater moves through a series of pipes that are placed in a trench filled with gravel and treated soil. A geofabric covers the top of the trench to ensure sand, dirt and other contaminants don’t enter the clean stone. Effluent then seeps into the ground, where microbes in the soil further treat it.
Other septic systems use alternative methods of wastewater disposal. For example, some tanks feature a grinder pump that liquefies solids in the tank before it goes out into the drainfield. This method also reduces the size of the septic tank and saves on maintenance costs.
In addition to keeping the tank and leach field clear of clogs, you should mow around the septic tank, driveway and parking area to prevent excessive water flow into these parts of your property. It’s also important not to drive or park over your septic drainfield, as this can crush the pipes within. You should also avoid planting gardens, bushes or trees in or near the leach field, as their roots can damage it.
The Inlet and Outlet Tees
The inlet baffle (a horizontal section of piping that directs the sewage flow into your tank) and the outlet baffle (a vertical section of piping that directs the wastewater flow out of your tank) are vital components of your system. If either one is missing or not functioning properly, wastes could flow straight from your septic tank to the absorption field, causing pipe clogs and premature system failure.
The septic tank is a settling basin: Heavy solid wastes (sludge) sink to the bottom of the tank, where bacterial action reduces them by as much as 50% over time. Lighter solids, such as toilet paper and hair, rise to the surface as a floating layer called scum. The sanitary tee (a PVC “T”-shaped fitting) ensures that these lighter solids do not escape from the tank into your house sewer.
If the sludge and scum layers become too close to the inlet or outlet tee, they may mix in the house sewer, causing a clog that can lead to septic tank and drain field failure. To prevent this, the inlet and outlet tees should be at least two to three inches higher than the bottom of the tank’s liquid layer.
To measure the liquid depth in your septic tank, use a stick to poke down through the wet sludge layer and mark where it stops. Then use the stick to pull up through the sludge layer and make another mark where you feel resistance. This is the maximum liquid level in your septic tank.
In addition to the septic tank, you need a watertight and well-maintained house sewer that connects to the septic tank. The slope of the house sewer should be a minimum of one to two percent, which is a drop of about one inch in eight feet. Install a cleanout (Figure 3) at each end of the sewer line and wherever it turns a corner at or near your home.
Your septic tank needs to be pumped every 2 to 5 years to remove the sludge that settles at the bottom of the tank. You should also inspect and clean your baffles, tees and other parts of the septic system on a regular basis. A reputable, licensed septic pumper will check that these vital components are in good condition and working correctly.
The Lid
The lid of a septic tank is often one of the hardest parts of the whole system for homeowners to find, especially if it has been buried. There are a few different ways to locate the lid, but the easiest is to look at the original septic plans that came with your house when you first bought it. These will give the location and dimensions of the tank in relation to your home, making it easy to find.
Another good way to find the septic tank lid is to follow the sewer pipe that runs out of your basement. It should go down a few feet and come out somewhere in the yard. If you can’t find it, try walking around the yard and poking the ground every few feet with a metal probe. Lids are buried about a foot deep, and you may be able to feel the bump of it under your feet.
If you are having trouble finding the septic tank lid, it is a good idea to consult a professional. The tank contains noxious gases that can be dangerous for children and pets, as well as to anyone who accidentally falls in. There have been a few cases over the years where people have died after falling into septic tanks. One such case involved a young child who disappeared at a birthday party and was found dead inside the tank later on.
Once you have located the septic tank lid, it’s a good idea to mark it in some way so that you know where it is and can easily find it again. You can place a small ornamental fixture on top of the lid to indicate where it is, such as a decorative rock or flag. This will also keep people from driving over or parking on the lid, which could cause damage to your septic tank or drain field.
If you are going to handle the septic tank lid, you should always wear rubber gloves and protective gear. It is also a good idea to have a second person with you to help out in case there are any problems or issues that need to be addressed right away.