In a small car park, in countryside outside Solihull, an affluent town in England's Midlands, a yellow box has been painted on the tarmac, next to a sign saying, "Visitors here." This would not be unusual in a museum, but this is Barston sewage-treatment works, which cleans the foul water of three towns and villages, and where visitors usually have hard hats and trucks, not Size 4 feet and school lunchboxes. But beside the yellow box is a trailer housing a classroom. Every day of the academic year, this sewage school is open for business.
There are five such trailers—"education centers"—like this one, in five water- and sewage-treatment facilities run by Severn Trent Water company. Five teachers have been loaned from elementary schools and spend their days, every day, teaching the same lesson about how dirty water is made clean and what happens after we flush and forget. Last year, 22,000 children went to sewage school entirely at Severn Trent's expense.
Barston's teacher is Malcolm Smith. He usually teaches 10-to-11-year-olds in a nearby school, but he volunteered for this assignment three years ago, and the topic fascinates him still. He's an engaging teacher. After the children arrive, noisily, Smith points to a truck trundling past. "That's a poo truck," he says, and though these children are 10 or 11 years old they are young enough to giggle at the word. Their nervousness abates.
Smith runs through a short lesson on the water cycle. But what the children want, and what they will now get, is a tour of a working sewage-treatment plant.
A yellow line representing the designated tour route has been painted onto Barston's paths and roads, past the gritter and the compactor, round the sedimentation tank, up to the bacti-beds, and ending up at the brook at the back of the works that discharges cleaned effluent into the River Blythe. Four million gallons of sewage arrive here daily, via the poo trucks and three sewers. There used to be 20 full-time workers to run the place, but in the age of computers, there's only one, a tall blond woman named Debbie. The plant is old, by sewage-works standards. It has been modernized, but if there is high technology in use, it's not obvious to the class from Balsall Common, who peer down into the gushing brown flow of the initial screening section, in a seemingly low-tech big hole, and gaze at the compactor, two huge tubes that are expelling toilet paper and other easily filtered matter. "Why isn't it switched on?" says one child, but it is. It's just glacially slow. The children are disappointed by the lack of action, but they perk up when Smith says he's seen a £20 note in there—and a dead rat. They move in single file to the gritter, which removes grit—and also thousands of kernels of undigested corn. "You'll see peas, too," says Smith. "Any vegetable that you don't chew enough, and that you don't have time to digest ends up in the gritter." The grit ends up in an open Dumpster, so that happy birds can pounce and peck at their everlasting corn supper.
We move to the sedimentation tank. Smith points out the layer of fat—pale beige, disgusting—floating on the surface of the sedimentation tank, where a scraper is constantly stroking the 13-foot-deep walls, so that the sludge settles. That's what happens when you pour oil down the sink, says Smith, hoping the children's obvious distaste will make environmentalists of them. He ignores a condom lying on the surface of the tank. "Adult balloons," he says later, out of the children's earshot. "You see them all the time." Then, it's the bacti-beds: eight flat circular tanks filled with stones that are covered with bacteria that eat the deposits in the wastewater. They are eaten in turn by microorganisms that are eaten by the happy crows perched on the glistening stones, and on the long mechanical arms spraying wastewater, powered by their own momentum. The system is Victorian and still works perfectly, but bacti-beds can stink. Some works have had to set up special odor hotlines so irate customers can call in their complaints.
At Barston, there's no smell, but there are flies. Clouds of them, bigger than gnats, dive-bombing our heads. In summer, it's worse, says Michaela, who has worked for Severn Trent for years and who, when given a choice between retirement or moving into the education department, jumped at the latter chance. She's proud that, of England's 10 water authorities, only Severn Trent Water has poured money into education. The water companies are required in their operating license to have an educational component, but only Severn Trent Water spends $250,000 or more each year on teachers' salaries alone. The CEO thinks elementary-school children might work for the company after they graduate from college. Certainly, the children of Balsall Primary School show none of the usual bored-on-school-trips symptoms. They troop when asked to troop, they listen when being educated, they peer at the canal taking the cleaned effluent into the river system, and they have enough curiosity after an hour in the cold to ask questions.
This isn't to say they're enlightened. They may know what a microorganism is and does, but the concept that No. 1s and No. 2s, as they call them, carry on existing once they've left the toilet bowl is a revelation. There is still plenty to be learned back in the classroom in the form of sewage soup.
Smith has had to leave, and Derek, the boss of the education department, has stepped in. He's going to make "sewage soup." In this exercise, a tank full of tap water gets dirtier and dirtier as the children think of things they've put down the drain and toilet that day and add them to the tank. Shampoo, soap, toothpaste, washing powder, rice, salt. "A No. 1," says one child, before grimacing as she pours what she thinks is urine into the tank (it's diluted lime juice). Toward the end, someone finally volunteers "a No. 2," plopping it into the tank with cries of distaste from the class, who think it's real (it's Weetabix soaked in water). When it's the turn of Nelson, a preposterously good-looking 10-year-old, he suggests a chocolate bar wrapper, because he flushed one down the toilet that morning. "You did what?" says Derek. "I don't know whether to let you have a go or to clout you."
Nelson's ignorance is only normal. He does what most of us do: He flushes and forgets. He didn't know before today that a hosepipe uses two and a half gallons of water a minute, or that oil clogs sewers, or that chocolate wrappers shouldn't be flushed. He's a child of his throwaway time.
Before the class leaves, I ask Nelson if he'd still throw a candy wrapper down the toilet. He says yes. I tell him I've been down a sewer and that it's not very nice, and how would he feel if he had to go and fetch the wrapper and clean the water? The admonishment sinks into Nelson's brain like oil into a sedimentation tank. He grins like an imp. "I'd send my brother."
Rose George is the author of The Big Necessity: The Unmentionable World of Human Waste and Why it Matters.