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What Is A Septic System & How Do They Work?

Wondering what a septic system is and how they actually work? Follow our guide as we explain the different types of septic tanks and how they benefit your home!

Effective wastewater management is crucial to ensure a healthy and hygienic lifestyle. No wonder septic tanks have become such an indispensable part of every household.

That said, most homeowners are often unaware of the working principles of septic tank systems and fail to maintain the quality of their residential septic system. Identifying the issue when their septic tanks start to act up becomes quite challenging because they don’t know how the system works.

However, there’s no need to get flustered because we’re here to help you. Today, we’ll answer the most grilling question about septic tanks: what is a septic system, and how does a septic tank work?

Parts Of A Septic System

Before we discuss how a septic tank works, let’s talk about the different components of a septic tank. The main drains collect and transfer solid and liquid wastewater to the septic tank from your household.

Secondly, further treatment tanks contain anaerobic bacteria to break down the collected wastewater through bacterial activity. A septic system also features a disposal area for safely dispersing the treated water within your residential property.

Diagram Underground Septic Tank System

Types Of Septic Systems

1. Primary Systems

They constitute a single septic tank and are common in any residential household. A septic drain field accepts, treats, and disperses wastewater in these septic systems. The heavier, solid wastes sink to the bottom of the tank forming a layer of sludge and scum.

At the same time, the grease and fats from solid or liquid waste get deposited at the top. Then, anaerobic bacteria naturally act on the wastewater to break the organic material down before it enters the effluent disposal area.

2. Secondary Systems

These have a large septic tank with several additional treatment tanks for wastewater disposal. The first treatment tank is similar to the single septic tank of the primary system, while the second treatment tank promotes the aerobic breakdown of wastewater. By mixing air with the collected wastewater, the second treatment tank facilitates bacterial breakdown for effective wastewater treatment.

Simultaneously, the third tank lets all solid wastes settle at the bottom. Some secondary septic systems also have a fourth treatment tank to disinfect the wastewater through UV saturation or chlorination. And the treated wastewater from this type of secondary septic system is much safer than the primary one.

Effluent Disposal

All septic systems have an effluent disposal area for the proper dispersal of the treated wastewater throughout your property, mostly underground. Discover what sullage or grey water, or effluent is.

The most common effluent disposal types include:

  • Absorption and transpiration trenches
  • Subsurface irrigation
  • Mounds and wick trenches

How Does A Septic System Work?

A. Conventional Septic Tank Design

A conventional septic system usually features a plastic or concrete in-ground tank containing bacteria and microorganisms. The solids settle in a conventional septic tank, allowing the microorganisms to break down the organic waste materials, while the untreated waste is stored in a separate chamber.

Furthermore, conventional septic tank systems work to separate fats and solids from the liquid through bacterial digestion in two separate chambers.

A quality septic tank must have three layers. Firstly, a fat layer where the scum floats to the surface to reduce foul odour. Below the scum layer, a transparent effluent layer and a sludge layer of solid waste should be at the bottom.

The effluent exits out of the septic tank through an outlet pipe and gets discharged into a drain field or a series of perforated pipes upon entering the new effluent. Not to mention, a conventional septic tank system’s entire working principle depends on gravity and bacterial activity.

Remember that the septic tank doesn’t kill harmful bacteria and organic materials, so the effluent must be cautiously treated to avoid health hazards. Once the effluent leaves the tank, it enters the absorption trenches and transpires or evaporates through the activity of plants or gets absorbed by the surrounding soil.

B. Package Treatment Plant Design

1. Primary Clarifier Chamber

The wastewater from your bathroom, kitchen sink, toilet, and laundry initially gets collected in this chamber. All the solid wastes settle at the bottom to form a sludge layer where the anaerobic bacteria digest the waste materials.

2. Aeration Chamber

After the primary treatment, the wastewater enters the aeration chamber, where the air mixes to facilitate aerobic digestion. This aerobic digestion process is much quicker than anaerobic digestion and leads to the secondary treatment of sewage.

3. Settling Chamber

Once the wastewater goes through aerobic digestion, the solid material settles further in this chamber, creating a clear effluent. It’s the final treatment process, after which the treated wastewater goes to an underground irrigation system from the septic tank for its dispersion.

4. Chlorination Chamber

Some package treatment plants come with a chlorination chamber to purify the wastewater. The water is exposed to chlorine in this chamber, where all the toxic microorganisms, like harmful coliform bacteria, are killed before the water goes to the irrigation bed.

C. Septic Tank With Sand Filter

A septic tank with sand filters is pretty standard in rural areas to treat wastewater in a sustainable and environment-friendly way by reducing health risks. In these septic tanks, the subsurface structure is usually sand-mound and remains filled with sand.

The wastewater percolates through this sand or gravel filter during the wastewater treatment. Moreover, the sand catches any solid material and offers a suitable environment for good bacteria or other microorganisms to digest the wastewater while reducing pollution.

Once treated, the effluent gets delivered into the subsurface irrigation systems, underground trenches, or any alternative systems approved by the local government.

Common Issues With Septic Tanks

Fixing Septic Tank Pipe Underground Muddy

1. Excessive Sludge

Too much sludge deposition is a common problem in all septic tanks, and it can result in clogged pipes or absorption trenches because solid human waste particles remain untreated. Don’t attempt to DIY a blocked sewer drain. Instead, call for professional help.

2. Excessive Water Build-Up

Poor wastewater flow or septic system overuse can lead to excessive water entering the tank and the adsorption trenches. Under these circumstances, untreated solid wastes might get pushed out of the tank’s inlet pipe and outlet pipe and clog your drain pipes.

3. Toxic Chemicals

When toxic chemicals, such as commercial cleaners or bleach, enter the tank, they can kill the good bacteria and disrupt the waste digestion process.

4. Slow Water Drainage

Slow water drainage indicates that your septic tank is failing due to drain blockages, particularly your main drainage pipe. Similarly, if the pipes make gurgling sounds or your sewerage system gives off foul smells, it’s time to call your emergency plumber to take a look at the septic tank

Knowing Your Septic System And How They Work

There can be no compromise regarding maintaining your septic tank’s health. Understanding how a septic system works can make all the difference in keeping the tank in top-notch condition.

You can also look for signs to determine whether your septic system works properly, such as regularly checking the water drainage and sludge level. Not to mention, timely pumping of the septic tank can help in desludging to avoid clogging your pipes.

And if your older systems are making gurgling noises and producing foul odours, replace them as soon as possible to avoid a plumbing disaster like backflow. Check out the signs you need a backflow repair.

Contact us for your Sydney septic service professionals, have your tank pumped, on-site sewage system, septic tank maintenance and other plumbing needs. We’ll maintain your plumbing adequately with our home maintenance services and avoid costly repairs.

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