OVER the years, it's become as much a part of Worcester's folklore as the Cathedral and the River Severn, albeit a rather less attractive one.

The pong from the sewage treatment works at Lower Wick is something of a local institution.

Periodically it drifts across the neighbourhood, especially if the wind is in the right direction and the weather is warm.

Generations of experts have promised to do something about it, but so far the whiff appears to have defeated their most energetic efforts, surfacing through all the technology like the bad smell it is.

However, Bad Smell now appears to have met its Armageddon.

The commercial giant Severn Trent Water Ltd, which runs the 50-acre site sandwiched between Bromwich Road and the River Severn, is investing mega bucks to squash the stench once and for all.

Hopefully.

Of course, there is the dictum that if you buy a house within sniffing distance of a sewage works, you must expect the odd odour. Just as if you choose to live next to a farm, it's no good complaining about the pigs squealing.

But STW wants to be a good neighbour, so it called in another team of experts and, based on all the new techniques now available, an improvement programme is being carried out.

Whether it proves to be any more successful than those that have gone before, remains to be seen, but it won't be for the lack of trying.

The best part of £10m has been spent on the site in the past 10 years.

"This is not a messy place," emphasised Ian Harrison, the sewage treatment works assistant manager operations. "It's state of the art in the sewage treatment world."

Computers hum, displays flash and machines appear to do the lot, with barely a human hand in sight.

There was a time when Worcester was at the cutting edge of sewage disposal, which must be some claim to fame.

On the Lower Wick site in 1915, it introduced the world's first full-scale aeration system for sewage treatment.

Then, as now, the works were the end of the line for the city's two main sewers, one coming in from St John's, the other passing beneath the river to arrive from Diglis.

The sewage was treated and then emptied back into the Severn as clean water just below Diglis Weir.

Today, about 35 million litres of water a day are poured back into the river, with the drawn-off treated sludge taken by lorry to be spread on farmland.

So efficient has the system become that water takes less than 18 hours to pass through the plant, having arrived via the huge pipes as raw sewage.

Solids take rather longer, treated sludge having a 30-day turn-round time.

The sewage treatment works were built on the west bank of the river at Lower Wick in 1908 on the site of Bromwich Farm and were owned by Worcester City Council until 1974, when Severn Trent took over.

Since then a steady programme of modernisation has taken place, leading to £5.5m being spent last year on a new Activated Sludge Plant to improve the final effluent quality.

But still the occasional whiff persisted and so ST brought in a team of site investigators "to pinpoint odour sources and control emissions".

They produced a delightfully named "odour map", which pointed its accusing finger at three areas of the plant - the digester feed well, the sludge thickening plant and the imported sludge reception area.

This has resulted in a further £300,000 being spent specifically on those locations, with work starting in October.

Hopefully, that will hit the pong on the head once and for all.

If it doesn't, no doubt folk will soon be on the phone.

To anyone not au fait with the niceties of raw sewage treatment, I would just like to make two points.

A. It doesn't smell or look like you would expect it to.

B. It can contain all sorts of things that wouldn't normally go down your sink or toilet - such as large pieces of wood, builders' rubble, bits off supermarket trolleys and even the occasional human body.

There is also a lot of storm water from roadside drains and the whole mixture has a very strange smell all its own.

In the process of its treatment, gas is drawn off and, ingeniously, used to heat the near-by Lower Wick Swimming Pool. Excess is burnt off via a flame stick.

"You could say this was an original re-cycling system," said Ian Harrison. "The sludge goes to agriculture, the clean water back into the river and the gas heats the swimming pool.

"And all the break-down is by natural bacteria."

And now the smell shouldn't get re-cycled either.