If you live in a rural area without a public sewer system, you’re most likely using a septic system in your home. This plumbing machinery plays a very important role in the disposal of wastewater and solid waste from your home’s sink, toilets, and bathroom.
Many people who use septic systems do not actually realize they’re using one until there’s a failure in the system. If you’re wondering what a septic system is or if you’ve heard about it, but wondering how it works, read on to learn what septic systems are, and how they work.
What is a Septic System?
Septic systems are underground wastewater treatment facilities composed of a septic tank and a drain field. They are mostly used in rural areas without centralized sewer systems. According to the U.S environmental protection agency, septic systems are structures that use a combination of nature and technology to treat wastewater emanating from bathrooms, kitchen sinks, and the laundry.
The main features of a septic system today include a septic tank and a drain field or a soil absorption field. The drain field is a shallow, sealed, excavation created in unsaturated soil.
How Does the Septic System Work?
In a septic system, water runs out of the building in one main drain pipe and empties into the underground septic tank. The septic tank (a buried, water-tight container commonly made of concrete, fiberglass, or polyethylene) then digests the organic matter content in the waste. It separates floatable matter, such as oils and grease, and solids from the wastewater. The liquid separated is known as effluent. Soil-based systems will discharge the effluent from the septic tank into several perforated pipes buried in a leach field or chambers to slowly release the effluent into the soil.
Some alternative discharge systems use pumps or gravity to aid the effluent discharge through sand, and organic matter, such as peat or constructed wetlands, to remove or neutralize pollutants like disease-causing pathogens, nitrogen, phosphorus, and other contaminants. Some alternative systems are designed to evaporate wastewater or disinfect it before it is discharged into the soil.
Here’s a flow of how a typical septic system works to discharge fluid from your household plumbing:
- All water leaving the building plumbing system runs into one main drainage pipe, emptying the wastewater into a septic tank.
- The septic tank holds the wastewater long enough to allow solids to travel to the bottom of the tank, forming a sludge, while the oil and grease float to the top as scum.
- There are compartments and a T-shaped outlet that prevent the sludge and scum from leaving the tank and traveling into the drain field area.
- The separated liquid wastewater (otherwise known as effluent) will exit the tank into the drain field since it can pass through the compartments.
- Pretreated wastewater then discharges through piping onto porous surfaces that allow wastewater to filter through the soil. The soil absorbs the wastewater, treats it, and disperses it as it percolates through the soil. It discharges into the groundwater.
- Note that if the drain field takes in excess water, it can lead to flooding. This can cause sewage to flow back to the ground surface or create sewer backups in your toilets and sinks.
- Finally, the wastewater seeps into the soil, eliminating the harmful coliform bacteria, viruses, and nutrients. Coliform bacteria is an indicator of human fecal contamination.
Types of Septic Systems
While the basic layout and principle of operation of a septic system remain universal, their design and sizes can vary widely. Common factors that influence this variation include the size of your household, soil type, site slope, size of the lot, proximity to sensitive water bodies, local regulations, and several other factors.
Here are four examples of the most common types of septic systems in use today:
Septic Tank
This is a buried, watertight tank designed and built to receive and partially treat domestic wastewater. Heavy solids separate and settle to the bottom of the tank while oil and grease and lighter solids float on the top. The wastewater is then discharged to the drain field for further treatment and dispersal.
Conventional System
This is a decentralized wastewater treatment system made up of a septic tank and a trench or drain field. The drain field is a bed subsurface wastewater infiltration system. This type of septic system is usually installed in a single-family home.
Chamber System
The chamber system is a typical example of a gravel less system. This consists of gravel less drain fields, which are gaining increasing acceptance in many states as an alternative technology for replacing gravel systems. They are available in many forms, including open-bottom chambers, fabric-wrapped pipes, and synthetic materials such as expanded polystyrene media. The gravel less septic systems can be constructed using recycled materials.
Drip Distribution System
The drip distribution system is an effluent dispersal system applicable in different types of drain fields. Its main advantage is that a large mound of soil is not needed since the drip laterals are inserted into the top 6-12 inches of soil. However, the drip distribution system requires a large dose tank beside the septic tank in order to accommodate the timed dose delivery of wastewater to the drip absorption area. It also includes the supply of electrical power.
Signs to Help You Detect Failure in your Septic System
You’ll notice a foul odor around the house from your plumbing system. However, a foul odor is not always the first sign of a malfunctioning septic system. This means that a build of wastewater must have taken place over a period of time, maybe due to a blockage or overloading of the septic tank.
If you notice any of the following, do not hesitate to call a professional sewer and drain specialist that understands how septic systems work in the area.
- Backup of wastewater into household drains
- A terrible odor around the septic tank and drain field.
- Patches of lush green, spongy grass growing on the drain field
- Pooling water or muddy soil settled around the septic system or in your basement.
Have More Questions About Your Home’s Septic System?
Septic systems are a crucial part of any household. They are responsible for the disposal of wastewater from toilets, sinks, and showers. Without them, your home would be at risk for a number of serious health hazards.
To ensure that your septic system is working properly, it is important to have it inspected every three to five years by a licensed professional. The inspection should include an assessment of the system’s condition and any needed maintenance or repairs.