West Wales Waste engineer empting a cesspit

Everything You Need to Know About Sewage Treatment Plants

Sewage treatment plants are indispensable for safeguarding the cleanliness and safety of our water supply. They play a pivotal role in removing harmful pollutants and contaminants from wastewater before its release back into the environment.

In this article, we delve into sewage treatment plants, encompassing their purpose, operational principles, and the advantages of having one installed.

What is a Sewage Treatment Plant?

A sewage treatment plant, also known as a wastewater treatment facility, is a site designed for the treatment of both domestic and industrial wastewater to extract harmful pollutants and contaminants. The processed water is subsequently reintroduced into the environment, typically into a river or the ocean.

Such facilities are vital for preserving the health and safety of our water resources. Without them, our waterways would be subject to pollution, posing risks to human health and wildlife.

How Does a Sewage Treatment Plant Operate?

Wastewater purification in sewage treatment facilities involves a blend of physical, chemical, and biological methods. Although the precise procedures may vary by plant type and the required treatment level, the fundamental stages are consistent:


Initially, wastewater undergoes screening to remove large debris like sticks, rags, and plastics, using grates or screens.

Grit Removal

Subsequently, the wastewater moves to a grit chamber, where sand, gravel, and other dense materials settle and are then extracted for disposal.

Primary Treatment

Here, wastewater resides in large tanks, allowing solid particles to settle at the bottom for removal. This phase eliminates roughly 60% of the solids in the wastewater.

Secondary Treatment

The wastewater advances to a secondary treatment tank, where bacteria and other microorganisms decompose organic matter and extract nutrients such as nitrogen and phosphorus. This stage often involves aeration to stimulate the growth of these beneficial microorganisms.

Tertiary Treatment

Some plants include a tertiary treatment stage to eliminate any residual pollutants through filtration, disinfection, and chemical treatment.


Following treatment, the water is discharged back into the environment, usually into a river or the sea, where it dilutes and disperses naturally.

Benefits of a Sewage Treatment Plant

Environmental Protection

By extracting harmful pollutants from wastewater, sewage treatment plants play a crucial role in keeping our waterways clean and safe for human and wildlife habitation.

Public Health Improvement

Treating wastewater eradicates harmful bacteria and pathogens, thus curtailing the spread of diseases and safeguarding public health.

Water Conservation

These plants are instrumental in water conservation efforts by treating and repurposing wastewater, particularly critical in regions facing water scarcity.

Pollution Reduction

Sewage treatment plants mitigate pollution by removing chemicals, heavy metals, and nutrients from wastewater, contributing to a healthier environment.

Installing a Domestic Sewage Treatment Plant

Types of Domestic Sewage Treatment Plants

There are various types of domestic sewage treatment plants, including:

  • Septic Tanks: Ideal for properties with low wastewater volumes, separating solids from wastewater.
  • Aerobic Treatment Systems: Utilise oxygen to decompose organic matter, suitable for higher wastewater volumes.
  • Biological Filters: Employ filters to cleanse wastewater, appropriate for properties with significant wastewater volumes and can complement septic tanks or aerobic systems.

Selecting a Sewage Treatment Plant Installer

When choosing an installer, consider their experience, certifications, and the maintenance support they offer. A reputable installer should be knowledgeable about local regulations and provide ongoing maintenance to ensure the plant’s effective operation.

At West Wales Waste, we’re dedicated to completing our services from start to finish with full customer satisfaction. If you want to enquire with us about our sewage treatment plant services, click here. Or to find out more about our Sewage Treatment Plant Service, click here.


Sewage treatment plants are essential for the sustainability of our water resources, removing pollutants and safeguarding both the environment and public health. If considering a domestic sewage treatment plant, thorough research and selecting an experienced installer are crucial for achieving the best outcome.

With appropriate installation and maintenance, a sewage treatment plant offers numerous benefits, contributing significantly to environmental conservation and public health.