For several years, the share of domestic sewage treatment plants in wastewater treatment systems has been increasing, and for good reasons: it is a compact, efficient and easy to install device.

But what are the advantages and disadvantages of a domestic sewage treatment plant?

That’s what we’re going to look at in this particular article.

How does a Domestic Sewage Treatment Plant Work?

domestic-sewage-treatment-plants-advantages-disadvantagesTo fully understand the advantages and disadvantages, it is first necessary to explain how a domestic sewage treatment plant works.

The domestic sewage treatment plant is an all-in-one device: a plant has 2 or 3 compartments (depending on the technology), all contained in a single enclosure.

The station collects all the wastewater from the dwelling and transports it first to the first compartment: the settling tank, which acts as a septic tank.

In the settling compartment, the solids settle and form sludge at the bottom of the tank. It is this compartment that must be emptied regularly.

Following this, the wastewater is sent to the reactor, where it will be purified by the bacteria. A bacterial growth support is placed in the middle of this second tank, and the bacteria that grow there purify the water. To do this, it is necessary to provide them with oxygen: the domestic sewage treatment plant must therefore be permanently supplied with electricity.

Finally, the treated water arrives in the clarifier, where it undergoes a final settling stage. The sludge that forms in this tank is then returned to the settling compartment.

Advantages and Disadvantages of the Domestic Sewage Treatment Plant

Now let’s get to the heart of the matter: the advantages and disadvantages.


Let’s start with the bad news: the disadvantages.

The first disadvantage of the domestic sewage treatment plant is the operating system: it must be permanently supplied with electricity to operate. The annual cost of this consumption varies between £25 and £50.

This first disadvantage leads to a second one, which concerns only a handful of potential users: the domestic sewage treatment plant cannot be installed in second homes.

In the event of the power supply failing during a prolonged absence, the domestic sewage treatment plant will stop working, and will take several weeks to return to normal operation once the power supply is restored. Meanwhile, wastewater would be discharged into the environment poorly treated.

Finally, the domestic sewage treatment plant needs to be running steadily to be effective. It is generally quite sensitive to load variations: if you are away for more than 3 months, or if the dwelling is occupied in a fluctuating way, this can be a problem.


Overall, these few disadvantages are outweighed by the many advantages.

Firstly, the domestic sewage treatment plant is the most compact and discreet device on the market: with only 5 m² of floor space, it can be installed anywhere, even above ground, in houses without land or underground.

Its installation is also very easy: it is light, easy to transport and can be installed in one to two days maximum.

The system is also very reliable, very efficient and above all very well guaranteed. It is also a very flexible device, since manufacturers offer many different sizes, options and materials: enough to easily find the right fit for you.

Finally, its installation cost is slightly lower than other wastewater treatment solutions on the market.


The domestic sewage treatment plant has some disadvantages, but above all many advantages: compact, efficient and discreet, it can adapt to many situations and its installation is easy, inexpensive and fast in all cases. Its reliability and robustness make it a first-choice device!