Just like a water treatment facility, septic tanks are designed to treat wastewater right where it’s generated. But how? Where does septic tank waste go?
If we were to answer this question straight away, the answer wouldn’t make much sense. That’s because the final stage of where a septic tank waste goes is actually back to the ground.
However, septic tanks don’t just take the waste and throw it into your backyard. There are a few different stages through which the waste goes before it eventually reaches the ground.
To understand where septic tank waste goes exactly, we first need to cover the components of a septic tank and then break down how the waste is disposed of.
Septic Tank Components
There are some essential components that all septic tanks need to work properly, whereas other components may not be installed in all tanks, like baffle filters and gas deflectors.
With that said, let’s look at the components of a typical septic tank:
- Tank: this is basically the water-tight tank that collects all the wastewater flowing from your home. The tank is mostly made from steel or concrete, and it shouldn’t have any holes, cracks, or structural deterioration.
- Access ports: these ports act as a manhole, which a certified pumper uses to clean out your tank. These ports have to be big enough to allow pumpers to maneuver the hose to thoroughly clean the tank.
- Inlet and outlet pipes: the inlet pipe starts from your house and ends at the tank’s inlet baffle. Outlet pipes start from the tank’s outlet baffle, all the way to the leaching bed.
- Inlet baffle: this is a vital component attached between the inlet pipe and the septic tank. The baffle allows waste to go from the inlet pipe into the septic tank and not the other way around.
- Outlet baffle: the outlet baffle prevents scum and sludge layer from escaping to the leach bed, allowing only the liquid waste to flow through for further disposal.
- Gas deflector: when bubbles rise to the top, they may carry solid wastes along the way. A gas deflector acts as an outlet baffle guard, which prevents solid-carrying gasses from entering the outlet baffle.
- Effluent filter: although not all septic tanks are equipped with one, it’s recommended to add this filter as another safety precaution.
- Leaching bed: this is a series of perforated PVC pipes buried inside a layer of stone and topped with a layer of sand. This pipe network is the final stage of disposal, where the liquid wastes seep into the ground.
Where Does Septic Tank Waste Go?
Let’s start from the moment you flush your toilet, wash your hands, or take a shower. Blackwater (from your toilet) or grey water (from your sink and shower) will start to go down the pipes inside your house.
The waste then travels through the inlet pipe until it reaches the septic tank where it enters through the inlet baffle. This is where the wastes get segregated into three layers; scum layer, liquid layer, and sludge layer.
Inside the tank is where all the magic happens. When waste enters the tank, the sludge layer falls to the bottom, the scum layer floats to the top, and the liquid layer separates both of them.
Sludge Layer
The sludge layer is composed mostly of organic waste, which you can get rid of through two methods.
First Method
With the help of microorganisms present in the tank. These microorganisms start degrading the sludge layer by eating it up. This is why it’s not recommended to flush any harsh chemicals or oils, which may kill the microorganisms in the tank.
Second Method
Another way you can get rid of the sludge layer is with the help of a septic pumping contractor. This is when you pump all the sludge out of the septic tank.
After the truck pumps all the sludge out, contractors take the wastes to a treatment facility where they safely dispose of the wastes.
This step can be done during the tank’s regular maintenance.
Depending on the size of your septic tank, pumping the sludge layer can be done every 3-5 years.
Scum Layer
Dealing with this layer is quite easy. The layer will keep accumulating inside the septic tank until the tank is pumped during regular maintenance.
Liquid Layer
With the sludge layer and scum layer out of the way, you’ll only be left with the liquid layer.
The liquid layer will travel into the second compartment through a baffle, where further treatment takes place by the microorganisms inside the second compartment.
The liquid wastes keep accumulating until it reaches the outlet baffle, which will take the liquid wastes to the next stage.
Outlet baffles are equipped with an effluent filter, which prevents scum and other solid wastes from escaping to the drain field.
After that the liquid wastes have reached the tank’s operating level, they’ll exit the tank and travel to the drain field, commonly known as the leaching bed.
The PVC pipe network disperses the effluent allowing the liquid to seep into the ground where the bacteria and other organisms continue to break the wastes down.
In case you’re wondering, why are these pipes buried in stone and sand? The two layers help filter the wastes and get rid of any odd smell or odor.
To Sum Up
Septic tanks will collect all the wastes from your toilet, sink, and shower to start a three-step disposal system.
The first step is when wastes are collected and segregated inside the tank into layers; scum, liquid, and sludge layer.
The second step is where microbes filter the wastes from pathogens and degrade the sludge layer inside the tank by eating it. This will leave you with a scum layer and excess sludge. The scum and excess sludge layer are both pumped by a professional septic pumping contractor.
The third step is where the liquid layer is dispersed into the ground through a network of PVC pipes called the leaching bed.