If they are sometimes sensitive about the smell that occasionally wafts from their Holdenhurst Treatment Works then who could blame them?

After all, they work 24/7 to keep the place running, even, like Wessex Water’s divisional operations manager, Luke Beattie, coming out on New Year’s Eve or Christmas Day to manually shovel the impacted wet-wipes (of which more later), ear-buds and other unmentionables that get flushed down the borough’s lavvies, bunging up the works upon which we all depend.

Certainly they’ve spent £2 million tackling the niffy issue and, as one who regularly drives past the place, I have to admit things have got a whole lot better in that department.

“Sometimes it can smell almost sweet and that’s because of all the detergent and the bubble bath that goes into the water,” Luke says.

“In the summer it can smell worse because there’s less water coming out of the sky to move it all along the drains and it hangs around longer.”

Some folk have suggested encasing the entire works in an aircraft hangar arrangement but there are three excellent reasons why that won’t happen.

Firstly, the cost: “It would be about £20 million”, the danger: “The gases which dissipate harmlessly into the air could build up,” and the sheer size of the place; to me it looks bigger than Dean Court.

And anyway, the modern treatment process is actually very eco-friendly and so is the Holdenhurst site; covering it all up would decimate the family of deer who reside in the copse there, just as it would hamper the activities of the foxes and possibly badgers who live in the grounds.

Certainly the birds wouldn’t appreciate it; from the seagulls to ‘Dave’ the heron, the ducks who happily float on the pools, and the odd swan – Luke has waded in to rescue them before: “They can’t take off to get out” – it’s humming with natural life.

Before arriving I had vague images of dredging machines and chemicals and, of course, those round concrete containers with stones on top.

This misconception is common, says treatment manager for the South, Barry Gregory. “People think they know what we do but most don’t.”

But if you’ve ever flushed a loo in Bournemouth you have an interest in this place; not only does it deal with all that, it also takes the road drain water and the stuff that gushes out of our shower and off our roof.

When the sewage arrives it’s screened for grit and sand and for the hundreds and thousands of wet-wipes, sanitary products and other stuff which should NEVER be put down the loo.

“They say they are flushable but that’s a marketing ploy, all it means is that they’ll go round the U-bend,” says Luke.

These nasties end up at the works – if they haven’t already blocked the Bournemouth sewers first, binding with grease to create the notorious ‘fatbergs’ which are dangerous and unpleasant to destroy, because workers have to go down and do it with spades and risk infection or even explosion.

They perform a demonstration with two bottles. Both contain water, one has a ball of loo roll, the other a wet-wipe.

After two minutes’ shaking, the loo roll resembles a snow-globe; loads of tiny bits. It would, says Luke, take TWO YEARS of continuous shaking to even begin to disintegrate the wet-wipe.

Further evidence, if it was needed, is in one of the four skips that is sent every week to landfill – rammed with the aforementioned unmentionables. “Please, just put wetwipes in the bin,” implores Luke, explaining how even their biggest sewer – the monster Coastal Interceptor, which runs from Alum Chine to the Pier and is 2.5 metres in diameter – can suffer fatbergs.

After this necessary interlude the sewage is moved to primary settlement tanks via an underground pipeline and ‘suspended solids’ – their polite word for poo – are allowed to settle to form the sludge which is taken off to Berry Hill digestion plant where it will eventually end up on is pumped back to the aeration tanks to clean more sewage. Too much or too little of this vital stuff and it will show up on the monitoring equipment.

After more filtration and a final whizz through the Ultra Violet light chamber – UV light destroys the cells of any lingering bacteria – the clean water is pumped back into the River Stour.

Occasionally, says Luke, they get calls from anglers who complain of ‘black stuff’ going into the river.

“What’s actually happening is that when you introduce clear liquid to a brown river it looks black,” he explains.

The rushing sound as this happens is reminiscent of a waterfall. In fact, the whole place sounds like the Trevi fountains.

As I leave, surrounded by the excited children who have come on a school visit, I realise there are far worse places you could work. And if this place ever stopped working, so would the entire town...