2 January 1998

All sweet &clear in this sewage garden

Everything in the garden is lovely – and efficient too

Beautiful water features can take care of your bathroom

and kitchen waste as

Tom Montgomery explains

Everything in the garden is lovely – and efficient too

Beautiful water features can take care of your bathroom

and kitchen waste as

Tom Montgomery explains

IT LOOKS like any other idyllic string of wildlife ponds. Bees hum… dragonflies hover… a moorhen fusses among the reeds… fish splash. The country air smells fresh and clean.

But stretch credibility to bursting. Gone is your dodgy septic tank and iffy drains. What you are admiring is… your very own private sewage farm!

There are no offensive bubblings, not to mention odours, in this finely balanced eco-system. Bacteria devour your waste with the zeal of piranha fish; sunlight twinkles on aerated water swirling down cascades, sweetening the effluent. The roots of blooming rushes and plants help digest out more unmentionable particles.

By the time domestic flushings and emptyings have reached the final pond, their crystal clarity supports frogs, newts and carp. The run off, in at least one system, is into a loch used for drinking water!

It may sound unbelievable that the bathroom and kitchen sink can be plumbed into an attractive water feature but its an option that more environmentally-conscious rural dwellers are adopting.

&#42 Nature purifies

Natures ability to purify is not new. Water companies now use reed beds to clean up their act and ponds have been used in America and Europe. Eight years ago Iris Water and Design put together a treatment system that brought the two together. Pivotal was to create the ideal conditions where the essential micro-organisms could flourish and multiply.

Systems can be devised for single households or whole communities. They are especially suitable for sites where access is difficult, such as farms and isolated cottages. A typical layout consists of three shallow, inter-linked ponds attractively landscaped. Effluent enters about a metre deep into the first pond, which is rich in aerobic bacteria.

Their close relationship with algae is crucial to the cleansing cycle.

As the organic matter is broken down by the micro-organisms nutrients are released which support the thriving algae. They in turn produce oxygen in sunlight which is essential for these bacteria in the upper layers of water to do their job.

Preventing stagnation and keeping the surface water well laced with oxygen is a key element. Because effluent is continually flowing into the pond the oxygen level is boosted by pump-operated, sculptured cascades stimulating hillside streams. These are constructed from flowforms – petal-shaped granite dishes – where the water eddies in figures of eight and moves rhythmically for maximum aeration.

Any odour escaping from the bottom of the pond, where different bacteria are at work, is also eliminated. A little flocculation, which soon disperses, for a short time in spring is the only sign that this stage is little more than a salubrious cess pit.

Another important factor is the artificially created wetlands. As the waste water is gravity fed from the first to second ponds it passes through stands of common reed, yellow flag and reedmace planted in gravel. Their roots act as a biological filter, controlling the harmful bacteria but nurturing purifying micro-organisms.

&#42 Tidal movement

A control outlet allows the water to rise and fall in the reed bed, simulating tidal movement and enhancing the cleansing process.

"Water plants love and thrive on human waste. Animals as well," says Andrew Joiner, a partner in Iris Water. "We always thought ducks would stay in the final, cleanest pond but, no, you will find them splashing around in all of them."

Water clarity is markedly improved in the second pond. By the time it has passed through another wetland area into the final body of water it is clean enough to support birds, fish and insects. Discharge can be into a watercourse, soakaway or woodland absorption area.

Effluent can take weeks to pass through a complex which is robust enough to cope with unexpected surges of pollution.

Iris Water design the systems and sub-contract the digging and landscaping. Initial capital cost is several thousand pounds for a layout serving up to a hundred people but maintenance is minimal. "Just gardening, basically, with occasional checks on a small pump," said Andrew. "They will last indefinitely. You may need planning permission but its usually a formality.

"Before we established a track record we had difficulty convincing people these systems work, now they are surprised how well they do."

The firm has installed over 20 in the last eight years with few difficulties. Probably the most impressive was a three-pond development for the former Trossachs Hotel in an environmentally sensitive area near Stirling. Built for 500 people it empties into Loch Achray, used as a reservoir.

Iris Water, which specialises in larger projects, has also developed a cost-effective method of making liquid farmyard manure safe for crops. A large flowform, shaped like a giant shamrock, oxygenates and bacterially treats the effluent in a holding tank. Frankie van der Stok, who farms as part of a community near Buckfastleigh, Devon, uses two to deal with the dirty water from his 15 cows and followers. Its sprayed on the land via a pipeline running to the fields.

&#42 Three-pond treatment

A three-pond sewage treatment system for 80 people has given no trouble since it was installed four years ago. "We are extremely pleased with it," Said Mr van der Stok, who has introduced different types of ornamental fish. Wildlife includes water fowl and herons. "Its just like any other water feature. You can have a pleasant stroll round it without encountering anything offensive."

Other companies in this field include a close ally of Iris Water called Ebb & Flow which has received three Royal Horticultural Society awards for water landscapes since 1994.

Most active at the other end of the range – small systems for gardens – it is seeking to branch out into treating farm effluent with ponds and wetlands. Less than an acre of water would be needed for 150 cows.

&#42 Habitat creation

Enthusiasts see these water features replacing those which have vanished from the countryside. Rich, aquatic habitats can be created in gardens and fields simply by recycling waste water through an eco-friendly process that enhances, not damages, the environment.

&#8226 Inquiries: Iris Water & Design, Langburn Bank, Castleton, Whitby, Yorks YO21 2EU (01287-660002).

Ebb & Flow, Ruskin Mill, Nailsworth, Glos GL6 0LA (01453-836060).

A pump-operated sculptured cascade simulates hillside streams. Water eddies in figures of eight and moves rhythmically for maximum aeration.

Above:An aeration flowform for treating effluent on a North Yorks dairy farm. Left: Second pond in the sewage system at the former Trossachs Hotel.

Above: The first pond in the pond and wetland sewage system at the former Trossachs Hotel.

Right:A pond and wetland system for five people in a garden near Bath.