Your septic tank removes solid materials from wastewater before it enters the soil absorption field (drain field). Lighter materials float, called scum, and heavier materials sink as sludge. Anaerobic bacteria inside the septic tank treat the sludge and create gasses that escape through the vent stack at roof height.
A full septic tank can cause sewage backups in drains and toilets. Proper monitoring, assessments and maintenance ensure your septic system operates safely. Click the https://www.septictankarmadale.com.au/ to learn more.
A septic tank is a large, watertight, corrosion-resistant underground container that receives raw sewage from household plumbing drains. The tank provides time for solids to separate out of the wastewater and partially decompose in a state of anaerobic (oxygen-free) digestion. Its size depends on the number of bedrooms in the house; current regulations specify a maximum sewage flow per day of 120 gallons for design purposes.
Solid waste sinks to the bottom of the tank in a dense, viscous layer called sludge. Oil and other light materials float to the top of the tank in a zone known as scum, while a zone of relatively clear wastewater exists in the middle. The anaerobic bacteria in the septic tank begin to digest and decompose the solid waste, converting it into liquid form. The tank also contains a venting system that allows gases to escape.
The septic tank is equipped with an inlet wastewater pipe and an outlet septic field pipe. The inlet pipe is fitted with a check valve to prevent sludge from entering the tank, while the outlet pipe has an effluent filter to stop scum and sludge from leaving the tank and clogging downstream components.
A septic tank should be pumped by a professional every three to five years. Pumping it sooner will require the absorption field to work harder, which may result in premature wear and failure. The tank should be pumped out through the large central service hole, not the sanitary tee or baffle inspection ports; doing so through these ports could cause damage to the septic tank.
After the septic tank is pumped, wastewater flows by watertight 4-inch diameter pipes into the distribution box and then to the absorption field through perforated pipes. The distribution box ensures that each of the trenches in the absorption field receives an equal amount of wastewater to avoid overloading one or more of them. The trenches are buried in the soil and filter the untreated wastewater through rocks, dirt and sand.
It is important to keep landscaping, vehicles and equipment away from the septic system and the tank. It is also wise to map out septic tank and other system components or use permanent stakes to mark locations, which will help avoid damage while performing home maintenance or yard work.
The Drain Field
When wastewater leaves your home, it enters the drain field. Also called the absorption field or leach field, this area of soil is a crucial part of the treatment process. Here, solid waste is filtered by soil microorganisms, which are able to break down and absorb chemicals from the sewage.
The septic tank does the initial processing, but it can’t completely remove all the solid materials from sewage. When a homeowner uses a septic system, they must also follow septic tank maintenance guidelines and keep the solids to a minimum.
Wastewater is pumped from the septic tank into a series of perforated pipes buried in the drain field. Oils float to the top of the effluent, while the rest — known as sludge or scum layer — sinks to the bottom. The anaerobic bacteria in the septic tank do their best to break down the sludge, but once it’s been transferred into the drain field, the process takes a backseat to the soil microorganisms.
Often, the perforated pipes are surrounded by gravel to help evenly distribute the effluent across the drain field. Above the gravel is a layer of soil that filters the wastewater before it seeps into groundwater.
If you think you have a problem with your septic tank’s drain field, contact a professional. The issue may be a clogged inlet baffle or other problem, which requires specialized equipment to troubleshoot and repair. You should also avoid planting trees or shrubs over your drain field, as their roots could grow into and clog the pipes. You should also direct gutter downspouts away from your septic system to prevent water runoff.
A well-functioning septic tank and drain field typically work in tandem to remove dangerous disease-causing bacteria, viruses, and other contaminants from the household wastewater. The system can only do its job if you use the toilets, kitchen, and laundry as designed and follow maintenance guidelines to limit the amount of solid waste entering it. Periodic pumping and preventing the transfer of excess solids into the system can help ensure that it works correctly and protects your home from sewage backups and other unpleasant issues.
The Inlet and Outlet Tees
The inlet and outlet pipes of your septic tank are protected by baffles or sanitary tees. The inlet tee directs the incoming waste downward to reduce disturbance of the settled sludge layer within the tank. The outlet tee keeps the floating scum layer from making its way to your absorption field where it would quickly clog and reduce the efficiency of the system.
The septic tank baffles or tees should be made of acid-resistant concrete, acid-resistant fiberglass, cast iron, or PVC and should be well maintained to prevent clogs and leakage. The inlet tee should extend about 6 inches below the top of the sludge layer and the outlet tee should extend 2 or 3 inches below the bottom of the floating scum layer. These heights are important because if the inlet or outlet tee levels are incorrectly set they can cause septic system problems such as clogs, excessive sludge accumulation and/or improper drainage of the septic tank effluent into the absorption field.
If the septic tank is located close to the house the inlet tee may need to be lowered closer to the ground level to keep solids from reaching the waste line between the house and the septic tank. If you’ve recently had the septic tank serviced or are considering a new septic tank installation, be sure to have the inlet and outlet tee levels checked by a Licensed Septic Contractor to ensure they are correctly set.
A septic tank with two compartments is more effective than a single-compartment model because the second compartment allows for a better separation and settling of solids. In addition, the second compartment provides an additional layer of protection in case the first compartment fills with solids too quickly.
The inlet tee is usually a vertical section of piping that extends down from the tank opening. To be effective, it must extend below the top of the scum layer (where grease accumulates) and above the bottom of the sludge layer to prevent a scum plug from developing in the inlet pipe. The outlet tee should also be set at the proper height to ensure that any organic matter that floats in the tank is not carried away and into the septic field lines where it could clog and degrade the soil treatment area.
The Pump
The septic tank is a large, dual-chambered buried container made of concrete, fiberglass or polyethylene. Sewage from the home’s toilets, showers, dishwasher and garbage disposal flows into the tank, where the weight of the solids causes them to sink to the bottom. Bacterial action partially decomposes the heavier solids. Lighter masses, including grease and oils, rise to the top of the tank where they form a scum layer. The liquid in the middle of the layers is known as effluent and is the wastewater that leaves your home.
The liquid sewage is pumped out of the tank by a pump and is directed to the drain field. The pump must be able to handle the amount of wastewater entering the system and the amount of solids being pumped out. The size of the septic tank, the number of people in the household and the use of a garbage disposal affect how often the septic tank needs to be pumped.
A septic tank vent pipe, sometimes called a mushroom cap, releases the gasses created by the bacteria that break down sewage contaminants. These gases include hydrogen sulfide and other noxious odors. The vent also helps prevent a build-up of pressure that could cause the tank to stop or reverse its flow of waste.
When the tank is full, it must be pumped to avoid clogged pipes in the home and contamination of groundwater or surface water. Having the tank pumped regularly will extend the life of the soil absorption field and prevent environmental contamination.
An important consideration when selecting a septic system pump is how easy it will be to maintain and repair. A pump with easily accessible components and routine maintenance procedures is more cost effective than a high-tech system that requires special tools to service.
A septic system is an integral part of your property. Keep it free of play equipment and storage buildings, which can damage the tank and/or drain field. Don’t plant anything near the septic tank or drain field, and make sure the yard slopes away from the tank to reduce flood risk. Excessive rainfall, rapid snow melt or flooding can overflow a septic tank and wash wastewater into the yard.