From Sewage to Strangford

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Tertiary water filtering through reed beds
Mount Stewart Gardens

All the waste water we flush down sinks, toilets, and drains at Mount Stewart runs back into Strangford Lough – but don't worry, we're not flooding it with raw sewage! It's treated right here on the property to a very high standard, so we don't endanger the fragile ecosystem of the lough and its many unique habitats.

The property's own sewage system is the first step, but our natural filtration system adds that extra level of cleaning or polishing to the waste water. This ensures that our own lake and Strangford Lough remain in good condition for wildlife and people.

Extra filtering with no extra energy

We use a wetland tertiary treatment system, more commonly known as reed beds or filter beds. This method needs no electricity or other energy input from us, and provides an excellent habitat for wildlife such as dragonflies, insects and birds.

The treated waste liquid flows through several distinct stages that gradually improve the water quality.  

First, Mount Stewart's sewage treatment plant takes care of the basic cleaning of the raw sewage coming from Mount Stewart Mansion House and Visitor Centre.

Next, the waste water flows from treatment plant to the start of the reed bed system. The gravel beds act as a filter and the aquatic plants assist in providing oxygen to the bacteria which digest the nutrients, resulting in clean water.

The water trickles through a whole series of these reed beds, each one improving the water quality slightly. Finally, it flows out into the lake and is tested by our ducks and swans before it enters the culvert which flows into Strangford Lough.

Next time you visit Mount Stewart, keep an eye out for the reed beds – you can see them beside the path near the white stag. The tall reeds and dragonflies may look calm and peaceful, but you'll know they're working hard to keep Strangford Lough clean.