SERVICES

SEWAGE TREATMENT PLANTS

If you’re among the five per cent of UK homes too remote to connect to the main sewer system, there are a few options available to you, septic tanks or sewage treatment plants. Sewage treatment plants are fast becoming the preferred option for off-system homes, farms and businesses.

Affordable, clean and environmentally friendly, sewage treatment plants are now also a legal obligation if you plan to discharge your wastewater into a stream or ditch. 

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What types of sewage treatment plant can you buy?

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Market leaders Marsh Industries are best known for their innovative Ensign range, in which all products are unobtrusive, easy-to-install and approved for discharge into a watercourse.

Kingspan are known globally and their flagship model has to be the Klargester Biodisc. Its unique design uses a rotating biological contractor – essentially moving discs on which more bacteria can grow and flourish.

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What size sewage treatment plant do I need?

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It all depends on the size of your property and number of people that are going to be staying there. You must size the treatment plant for its potential occupancy not how many people are currently living at the property – it can save you money in the long run to over-estimate rather than underestimate when you’re at the planning stage. 

As an example, British Water Flows and Loads state that for a three-bedroom property you’ll need to size your treatment plant at five people.

When it comes to sizing a sewage treatment plant for commercial use, you’ll need to know what the PE number is. Standing for ‘Population Equivalent’, this relates to the number of workers using the building. For example, an office with 30 workers is thought to be equivalent to 10 domestic residents, so its PE number is 10.

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Running Costs

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We recommend that you have your sewage treatment plant emptied and serviced annually.

Sewage treatment plants also require a power source to run either a small air compressor or a system of rotating discs. The energy requirement is low but running power to the system is something to bear in mind when planning your installation. Also be aware that if several households are sharing a sewage treatment plant, you’ll need a shared supply with a separate meter so that you can accurately divide up the costs.

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How do sewage treatment plants work?

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The job of a sewage treatment plant is very simple. It cleans all the wastewater a building produces from toilets, showers, baths, dishwashers and sinks, so that it can then be discharged safely into a river or stream. With all the nasties removed. the treated water produced by a treatment plant should pose no harm to plants, wildlife or fish.

So how do they do this? All sewage treatment plants work in similar ways. First, the wastewater flows into the primary chamber, where gravity separates any solids from the liquid. The solids sink to the bottom to form what’s known as a sludge which will be tankered away later.

The remaining liquid flows into the second chamber for treatment. In this biological zone, compressed air is pumped in, and this added oxygen encourages the naturally occurring aerobic bacteria to flourish. Some sewage treatment plants also have rotating discs which give the bacteria a larger surface area to grow on.

At this point, the treated effluent goes into the final part of the tank – a calm area that allows the bacteria to settle at the bottom (for removal back into the first tank) while the clean liquid can flow out either to a watercourse (subject to Environment Agency consent) or to a ground soakaway field or drainage mound.

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What do I need to consider about where to install a sewage treatment plant?

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We will work with you to find the best spot for your sewage treatment plant, but there are a few things to bear in mind before deciding on the perfect place to site your sewage treatment plant.  Remember that building regulations insist that it should not be closer than seven metres from the foundations of your home, and 10 metres from the watercourse. Other than that, here are some other things to bear in mind…

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Can the lorry pull up close enough when it’s time to empty the tank?

Your sewage treatment plant will need emptying at some point, usually once a year. So, you’ll want to site it less than 30 metres away from some hardstanding, or the lorry will find it hard to pull up close enough.

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Can gravity help my sewage treatment plant to work?

Putting the sewage treatment plant downhill from your house means that gravity will help the wastewater along, without the need for extra pumps.

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Will we be able to smell it?

When working properly, sewage treatment plants don’t really smell that much at all, but when they are being emptied you probably will be able to smell it. That may just be once a year, but even so you’ll probably want to site it as far away from any inhabited buildings as possible.

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Will the noise of the sewage treatment plant affect us?

Some treatment systems are louder than others, but all will emit some kind of buzzing or gurgling sound. If you’re a light sleeper, it may be best to keep it away from under your bedroom window.

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How do I get started?

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The best way to get the ball rolling is to get in touch with Perryman Groundworks and get us in for a site visit. We can talk you through the options available and then put together a proposal that is tailored to you and your property.