Septic Tanks vs Wastewater Treatment Systems

When it comes to managing household wastewater, there are various options available which often comes down to septic tanks vs wastewater treatment systems.  These two common sewage treatment systems choices are septic tanks and waste water treatment systems. But which is the better option?

Understanding the differences between these two systems is crucial to making an informed decision for your home.  The decision of which type is suitable to your needs will also likely depend upon:

  • the visibility of the tank above ground,
  • the purchase cost and installation cost,
  • the maintenance involved,
  • electricity and annual costs,
  • replacement parts,
  • spares,
  • and any additional costs involved.

In this article, we will compare septic tanks and wastewater treatment systems, highlighting their pros and cons, to help you determine which option is best suited for your needs.

The Difference Between Septic Tanks vs Wastewater Treatment Systems

Septic tanks are underground tanks that hold and treat wastewater from a property’s plumbing system.

They work by separating solid waste from the liquid, allowing the liquid to flow into a drain field for further filtration. The purpose of septic tanks is to effectively and safely manage household wastewater in areas that are not connected to a centralised sewage system.

Wastewater treatment systems, on the other hand, are large-scale facilities that treat and purify wastewater from multiple sources before it is released back into the environment. These systems utilize various processes such as biological, physical, and chemical treatment to remove contaminants and pollutants from the wastewater.

The crucial difference between septic tanks vs wastewater treatment systems is their scale and function and the biggest difference between them, is the breakdown process.

While septic tanks cater to individual properties, wastewater treatment systems serve entire communities.

In terms of cost, septic tanks are generally more affordable to install and maintain compared to wastewater treatment systems.

Both septic tanks and treatment plants dispose of waste through natural processes or by releasing treated water back into the environment.

Maintenance of septic tanks involves regular pumping and inspection, while treatment plants require continuous operation and monitoring. Poor maintenance, for example, can cause soil contamination.

What Are Septic Tanks? Your Comprehensive Guide

The Environment Agency has introduced regulations to ensure the proper installation, operation, and maintenance of septic tanks and treatment plants to protect the environment and public health.

Septic Tanks

Septic tanks are underground wastewater treatment systems that are commonly used in areas without centralised sewer systems to treat wastewater.

These tanks are designed to collect and break down organic matter, solid waste and dirty water, releasing the purified water back into the soil through a nearby soakaway or drainage field, and sometimes even a drainage mound.

Proper maintenance and care of septic tanks are crucial to prevent costly and harmful issues, such as groundwater contamination and system failure.  That said, they are a convenient option.

Purpose of Septic Tanks

Septic tanks serve the important purpose of safely treating and disposing of household wastewater, including human waste and other organic matter.

By separating solids from liquids, septic tanks allow bacteria to break down waste, turning it into harmless byproducts and releasing the treated water back into the surrounding soil.

How Septic Tanks Work

Once wastewater enters the septic tank, gravity helps to separate the solids, fats, oils, and greases from the water.

The liquid portion then exits the tank and enters the drain field, where it undergoes further filtration as it percolates through the soil.

Meanwhile, the solids remain in the tank and continue to break down through the work of bacteria and enzymes.

Maintenance and Care Tips

Regular maintenance and care are essential for the proper functioning of septic tanks.

This includes routine inspections, regular pumping, and avoiding the disposal of harmful substances into the system. Homeowners should also be mindful of water usage and landscaping practices to prevent unnecessary strain on the septic system.

The Role of Septic Tanks in Domestic Wastewater Treatment

Septic tanks play a crucial role in the treatment of domestic wastewater, providing an efficient and cost-effective solution for households that are not connected to a centralised sewage system and filtering the solid matter out of sewage water.

This underground chamber, typically made of concrete or fibreglass, allows for the separation and decomposition of solid and organic matter from household sewage.

The resulting clarified liquid, known as effluent, is then discharged into a drain field for further filtration and absorption into the soil.

Understanding the function and maintenance of septic tanks is essential for homeowners to ensure the proper treatment of their wastewater and the prevention of environmental contamination.

How Long Do Septic Tanks Last? Everything You Need to Know

In the following sections, we will delve into the explanation of septic tanks and their importance in domestic wastewater treatment.

Components of a Septic Tank System

A septic tank system consists of several components designed to effectively treat and dispose of wastewater. The main components include the septic tank, multiple chambers, and the drainage field.

The septic tank is typically divided into multiple chambers to facilitate the separation of solids and liquids.

Solid waste settles at the bottom of the tank while liquids, or effluent, rise to the top.

This separation process allows for the anaerobic breakdown of waste, reducing the amount of solids in the effluent.

The effluent exits the septic tank through an outlet and is directed to the drainage field, also known as the leach field. In the drainage field, the effluent percolates through the ground, where natural processes further treat the wastewater before it rejoins watercourses.

Key parts of the septic tank system include the inlet, which allows wastewater to enter the tank, and the outlet, which directs the treated effluent to the drainage field.

The drainage field consists of perforated pipes or chambers that distribute the effluent into the soil for final treatment and disposal. It is important to ensure that the effluent quality remains within legally acceptable parameters.

The Tank, Drainage Field, and Maintenance Requirements

When it comes to septic systems, the key components include the tank, drainage field, and specific maintenance requirements.  Sewage drainage systems septic tanks are effective when a power supply and main sewage drainage connection isn’t possible.

  • The tank is the primary holding area for waste (creating three layers including a scum layer), solid matter and sewage, where natural bacterium processes break down and separate the solids and liquids.
  • The drainage field is where the treated liquid waste is dispersed into the surrounding soil for further purification.
  • Maintenance requirements for septic systems include regular pumping of the tank to remove accumulated solids, periodic inspection and potential repair of the drainage field, and overall monitoring of the system to ensure proper functioning and prevent any potential issues.

Understanding these key components and their maintenance requirements is crucial for ensuring the longevity and efficiency of a septic system.

According to building regulations, if it is not possible to connect to a main sewer, alternatives such as a cesspool, septic tank, or sewage treatment plant are required.  If your home is too remote to connect to a main sewer system you will also need to get off-mains drainage installed.

How Often to Service Septic Tanks

Septic tanks are low maintenance and only require de-sludging every 1-3 years to remove accumulated solids. Sewage treatment plants, on the other hand, require regular upkeep to ensure all equipment and processes are functioning properly.

Advantages of Septic Tanks

Septic tanks offer several advantages that make them a popular choice for wastewater treatment in residential properties.

One of the main benefits is their relatively low installation and running costs compared to more complex sewage systems. In addition, septic tanks facilitate the natural breakdown of waste by bacteria, which reduces the need for costly and energy-intensive treatment processes.

These tanks also require only once or twice yearly emptying, making them a low-maintenance option for homeowners.

To keep the bacteria in septic tanks healthy and running costs low, septic tank treatments can be used. These treatments contain beneficial bacteria and enzymes that help break down solids and organic matter, ensuring the efficient function of the tank.

By maintaining a healthy bacterial balance, homeowners can minimize the need for regular emptying and prolong the lifespan of their septic tank system.

Sewage treatment plants may require regular maintenance due to their complex machinery, but they produce minimal sludge, resulting in less frequent emptying. It is advisable to de-sludge the plant once a year to prevent any potential damage to the treatment chamber caused by solid accumulation.

Before purchasing it’s advisable to talk to a well-established expert so that you also fully consider the maintenance costs involved and the best septic tank for your location and needs.  Let us continue looking into the differences between septic tanks vs wastewater treatment systems.

Cost-Effectiveness and Self-Sufficiency

Different types of drainage systems offer various benefits related to cost-effectiveness and self-sufficiency. For example, green infrastructure drainage systems, such as rain gardens and bioswales, require minimal treatment compared to traditional grey infrastructure systems.

They are also self-sufficient, relying on natural processes to absorb and filter stormwater. This reduces the need for electricity consumption and regular servicing, resulting in cost savings and environmental benefits.

Similarly, permeable pavement systems promote cost-effectiveness and self-sufficiency by reducing the need for extensive treatment requirements. They allow stormwater to infiltrate the ground, minimizing the reliance on energy-consuming treatment facilities.

Their low maintenance requirements contribute to long-term cost savings and reduced environmental impact.

These benefits contribute to the overall environmental impact and sustainability of drainage systems by minimizing energy consumption, reducing the need for expensive treatment processes, and promoting self-sufficiency in managing stormwater.

By implementing these cost-effective and self-sufficient drainage systems, communities can save on operational costs and reduce their environmental footprint.

Which Septic Tank is Best for Your Home or Business?

Wastewater Treatment Systems

Wastewater Treatment Systems, or domestic wastewater treatment plants, are essential in maintaining environmental health and public safety. These systems are designed to remove pollutants and contaminants from wastewater before it is released back into the environment, preventing the spread of harmful substances.

There are various methods and technologies used in wastewater treatment, each serving a specific purpose in the removal and transformation of pollutants.

From physical processes that separate solid and liquid waste, to biological processes that utilize microorganisms to break down organic matter, these systems play a crucial role in preserving water quality and protecting ecosystems.

In areas where access to clean water is limited, wastewater treatment systems also serve as a means of reclaiming and reusing water resources, making them an integral part of sustainable water management practices.

A sewage treatment plant is a more advanced and sophisticated version of a septic tank that treats wastewater to produce a higher quality of effluent.

Understanding the importance of these systems and their various components is key to ensuring the preservation of water resources for future generations.

Advantages of Wastewater Treatment Systems

Wastewater treatment systems offer numerous advantages, including improved water quality, compliance with regulations, cost savings, durability, and sustainability.

These systems significantly improve the quality of water by removing pollutants and contaminants, ensuring that the water released back into the environment is safe and clean. This, in turn, helps to protect ecosystems and public health.

Businesses and municipalities that utilize wastewater treatment systems can ensure compliance with environmental regulations. By meeting these standards, they avoid costly fines and penalties, as well as potential damage to their reputation.

In terms of cost savings, wastewater treatment systems can significantly reduce the amount of water and chemicals needed for various industrial processes. This not only conserves resources but also reduces operational costs.

The systems are designed to be durable, with the ability to withstand heavy use and harsh conditions. This ensures that they have a long lifespan and require minimal maintenance and repairs.

Wastewater treatment systems also contribute to sustainability by conserving water resources and reducing pollution. This aligns with the growing global focus on environmentally friendly practices and sustainable development.

Overall, the advantages of wastewater treatment systems make them crucial for both environmental protection and economic efficiency.  You just need to be aware and compliant with regulations surrounding liquid effluent that is out from the tank and discharges into the drainage field.

It’s well worth reading about septic tank regulations, as in 2000, the Environment Agency changed the septic tank regulations and introduced what’s now known as the general binding rules.

Water Neutrality: Everything You Need to Know

Wastewater Treatment Systems and Their Purpose in Treating Domestic Sewage

Wastewater treatment systems are crucial for managing domestic sewage in communities.

These systems are designed to eliminate contaminants and pollutants from wastewater, making it safe for release back into the environment.

They play a vital role in safeguarding public health and the environment by removing harmful pathogens, chemicals, and nutrients from sewage before it is discharged into local waterways.

Wastewater treatment systems are essential for preventing waterborne diseases, protecting aquatic ecosystems, and ensuring a sustainable water supply for future generations.

Types of Wastewater Treatment Systems

There are several types of wastewater treatment systems, including media filters and aerobic treatment units.

Media filters work by passing wastewater through a bed of filtration media, such as sand, gravel, or coconut husk fragments, which trap and remove contaminants. These filters can be designed as slow sand filters, rapid sand filters, or multi-media filters, each with its unique design and components.

Aerobic treatment units, on the other hand, use oxygen and beneficial aerobic bacteria to break down organic matter and remove contaminants from wastewater. These units typically consist of aeration tanks where the wastewater is mixed and aerated, and a settling chamber where the solids separate from the water.

Using sustainable filtering media such as coconut husk fragments in both media filters and aerobic treatment units offers several benefits. These materials are renewable, environmentally friendly, and have excellent pollutant removal properties. They also promote the growth of beneficial bacteria, ensuring effective wastewater treatment.

Both media filters and aerobic treatment units play a vital role in removing contaminants from wastewater and promoting environmental sustainability.


Here’s a quick summary with some key takeaways from this article:

  • Choosing between septic tanks and wastewater treatment systems requires an understanding of their differences and advantages.
  • It is important to consider the pros and cons of each option before deciding on your home.
  • This article aims to provide information that will assist in determining the best option for managing household wastewater.

Hopefully, you understand more about septic tanks vs wastewater treatment systems and their differences.

However, if you have any questions or need further assistance and guidance, then please don’t hesitate to get in touch with us at Septic Tanks North West.  We are trained by suppliers in sewage treatment to the highest standards whilst maintaining a family-friendly and personalised service.

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Updated: January 9, 2024

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