What is a cesspit and how do cesspits work?

What is a cesspit?

Cesspits or cesspools are becoming less common with most UK households connected mains sewerage systems. Others that aren’t will more often use septic tanks or sewage treatment plants to treat their sewage.

Cesspits, however, as they have no outlet, are generally fitted as a last resort for when raw sewage could potentially be discharged into surface waters without being treated enough and pollute the surrounding environment as a result.

How does a cesspit work?

A cesspit is a sealed, waterproof tank buried underground that has no outlet and only a single utility hole cover for access by licensed waste collection companies, like Sweeptech. It is essentially a holding tank and when full the tank needs to be emptied.

In comparison, a Septic tank is a single or multi-chamber tank with a waste outlet that discharges to land by soakaway.

As there are no other openings in a cesspit, gas builds up in the chamber, meaning a cesspit needs a pipe to act as an exhaust.

Depending on use and solid fractions, these tanks will require emptying one to two times a year. You can tell the tank is full either by looking at the waste level in the tank or by using a remote monitoring system which informs you when it needs to be emptied.

Processing the waste

Once collected the waste is taken to a licensed Waste Water Treatment Works where it is screened to remove large objects that may block or damage equipment or pollute our rivers. This includes items that should never have been put down the drain in the first place, such as nappies, wet wipes, sanitary items and cotton buds, and sometimes even things like bricks, bottles and rags. Special equipment is then used to filter out grit, as this often washes into the sewer with wastewater.

Wastewater still contains organic solid matter – otherwise known as human waste. The waste is separated from the water by putting it into large settlement tanks, where solids sink to the bottom. The settled solids are called ‘sludge’. Large arms or scrapers help to push the sludge towards the centre, where it’s then pumped away for further treatment. The cleaner water passes over a wall near the top of the tank ready for the next stage of the treatment process.

The sludge that is collected at the start of the process can put it to good use. It can be recycled and spread to agricultural land for farmers to use as fertiliser, but it can also use it to generate energy.

After a number of further screening processes once the wastewater is clean, it can be safely returned to local rivers and streams. Putting clean water back into the river is very important, as it helps to keep water flowing and wildlife thriving.

Get in touch

If your property has a septic tank, you will need to be aware of new rules that came into full effect in 2020 prohibiting septic tanks from discharging directly into a watercourse, applying to both new and existing systems. If you fail to adhere to the rules, you could be hit with a fine of up to £100,000.

Get in touch for a bespoke quotation which will be subject to location and access requirements. There will be a need to get a hose from our Tanker to the Cesspit.

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