Britain water supply system:If you were to design Britain’s sewer system from scratch today, our existing sewer system is not the design you would choose, to say the least. But for much of the country, it is already too late. Most cities have systems that are almost constantly “baking” in sewage leaks.
If you want to understand how Britain got into a sewage crisis from which it may never quite recover, it’s best to start not this year, or last year, or the year England’s water industry was privatized (1989), but a year ago. and half a century ago.

It may seem odd to begin describing Britain’s water crisis in 1856, but as it happens, a fateful decision was made that year – a decision that set us down the path we’re still on today, with concerns about the repeated flow of sewage into rivers. Anger is building and little progress has been made on the problem. 1856 proved to be the moment when the entire structure of urban water systems in Britain (and much of the rest of the world) was dismantled.

Today’s water industry has many complexities – financing companies, the regulatory bodies that oversee them, the nature of water treatment – ​​but the reality here is surprisingly simple. It goes back to the pipes, or more precisely, what goes through the pipes.

If you live in a big city like London or Glasgow, when you flush the toilet, the water goes down the drain. The same goes for the gray water that comes out of the sink or the back of the washing machine.

But also rain – and that’s the main thing. Rainwater that runs off roofs, sidewalks, or roads also goes down the same gutters and into the same sewer pipes. This is the so-called “mixed rainwater and sewage system”. The biggest problem with combined systems is that whenever it rains heavily, the system is susceptible to so-called combined sewage overflows. Rainwater essentially floods the sewer system and its pipes and flows through outlets into rivers or the ocean. These leaks should be rare and only occur during heavy rains, but (and this point is hard to overstate) they are not a system failure – they are the system.

With such a combined system – in other words, configuring the pipes as they are – it is not actually possible to 100% prevent all sewage leaks, unless you cover most of the country with treatment plants or build something much larger than the original tunnels. and water tanks. You can imagine. Either that or you can let the sewage back up into people’s homes. This is the logic of pipelines. Now, if you were to design a UK sewer system from scratch today, this is not the design you would choose, to say the least. You will most likely choose something else – a separate system with a sewer pipe and a completely separate rainwater pipe.

Even with a standalone system, there are still challenges. First, road water is very dirty, so it is not recommended to let it flow directly into the river. However, individual systems are now considered the gold standard as they help protect sewage treatment plants from flooding during heavy rains.

But for most of us, it is too late. Large urban areas in the UK have such combined systems which dispose of sewage almost continuously. While some in the water industry suggest that all new sewer systems since the 1960s have been the gold standard “separate,” as we’ll see later, the reality is much murkier. But here’s the thing. In a parallel universe, these combined systems might not exist at all. A sewage overflow may be just a dream.


This brings us back to the fateful decision of 1856, a decision made in light of what would become known as “The Big Stink.” Victorian London struggled with a worsening sewage problem. There were many outbreaks of cholera, the most famous of which was the cholera epidemic of 1848, which killed tens of thousands of people. Social reformers such as Sir Edwin Chadwick started a movement for change and called on the authorities to clean up the city, but things seemed to be getting worse and worse.

As Stephen Halliday documents in his master’s study, The Great Smird, the advent of flush toilets had a negative effect, causing a dramatic increase in the amount of liquid entering the era’s primitive sewage systems. At that time, there was no concept of sewage treatment as we see it today. In fact, more and more sewage is being washed into the Thames and its tributaries. The more sewage enters the river, the smellier the water becomes, and more importantly, the more people get sick, since most households get their drinking water from the same river.

Eventually, authorities launched a series of investigations, the first of which was led by Chadwick. His vision of London’s sewer system was not unlike the independent systems that people still fantasize about today: sewage flows into one pipe and rainwater into another. Finally, the wastewater will be treated and turned into manure that can be used as fertilizer. So there was an exciting moment in the mid-19th century when it seemed that London would finally have a separate sewer system. In fact, Chadwick was not the only one to advocate this: other engineers came up with detailed plans to build separate pipes for sewage and rainwater. But in the end the commissioners settled on another design – championed by Sir Joseph Bazalgé.
Bazargue was a civil engineer and was appointed chief engineer of the Metropolitan Works Board. In 1858, when the stench of the British Parliament Buildings became so unbearable that they had to be abandoned, his solution was the sewage system we have today.

London’s domestic pipes and drains, carrying both sewage and stormwater, will flow into a series of sewers that run alongside embankments along the Thames and to the east of the city, where waste will be collected and then discharged into the Thames’ tidal currents. North Sea. This is how the sewage treatment system that most of us use today was born.

Where London leads, other countries follow. All other major cities in the country have adopted similar combined sewer systems – not to mention many cities and regions in Europe and North America. Bazalgette’s fateful decision, choosing to merge the system and ignore the protests of Chadwick and others, changed the world forever. Today, the Bazalgata sewer and other public works he helped build are recognized as extraordinary achievements. By helping to remove feces from the city, they prevented further outbreaks of cholera. He and his pipe saved countless lives.

Plus, they’ve stood the test of time. London’s sewage still flows through the brick and concrete tunnels laid by Basalgate and his engineers a century and a half ago. His system, developed when the city’s population was about 2 million, is now used by nearly 9 million. It is a miracle.

But it is still a combined system designed from the beginning to discharge sewage into the river during heavy rains. As the population and the size of Britain’s cities grow, more and more concrete and asphalt surfaces divert more and more rainwater down the drain, and these discharges are becoming more frequent.

Back in Bazalgette’s lifetime, London’s system had to discharge for about 12 days each year during the heaviest rainfall. Today there are more than 60 days in a year.

Here are the most important things you need to know about UK sewage systems. The first big problem is the system. We made the wrong choice. But if that’s the only problem, then maybe it’s forgivable. But unfortunately, this is only the beginning, as decades of underinvestment have made this unfortunate choice worse. This is the table of contents for the question. First, governments cut public investment in the late 1970s and 1980s (partly in response to Britain’s IMF bailout and partly as a choice of Margaret Thatcher’s government). In the 1980s, the UK had barely passed a set of European directives on water quality and sewage treatment systems (one of which banned dumping sludge into the sea, which we still did until the late 1990s). So the system was privatized. Sir Dieter Helm, an Oxford University economist and one of Britain’s leading infrastructure experts, said: “The idea was that from 1990 we needed a big investment in water, but the government didn’t.” This will have a cost – so the private sector should borrow money to invest in updating the water infrastructure.

“Balance sheets will be created – clean balance sheets with nothing to show (in fact [the company] won £1 billion) – and these balance sheets will be used for investment. “But balance sheets weren’t used for that. They were used for one of the biggest financial engineering efforts in economic history. “What the new owners of the company do is basically say, can we mortgage these assets? But then they distribute [the proceeds] to shareholders in the form of dividends. “More than thirty years later, we have not built new reservoirs, no new resources have been put in, and frankly, the condition of the sewers is not what it should be.”

The extent of the problem only gradually became apparent.

The reality of pollution is shocking

Let’s start with wastewater. When operating as intended, combined sewer systems should discharge very little load into waterways – if it rains heavily. When discharges occur, they must be very diluted as the effluent is carried off with liters of rainwater. but that’s not true. In much of England and Wales, many overflows discharge sewage even on the driest days. Estimating exactly how often this happens is a tricky business. Although water companies in England and Wales are producing more wastewater data than ever before (and notably more than most other countries, including Scotland, where only a fraction of the data is available), the numbers are not 100% reliable. In fact, the EPA says only 82% of pollution reports come from water utilities, with the rest coming from EPA monitoring or public campaigners.

It’s easy to assume that most pollution cases are caused by bad actors—someone pushes a button in a control room somewhere that releases sewage into a river or coast—but the reality is more prosaic and perhaps more shocking. Most spillways are simply tunnels connected to spillways or walls through which water flows when it cannot enter “normal” pipes. In other words, they are the system’s inability to cope with manifestations. Sometimes it’s because the pipes are clogged with debris, or it’s every sewer’s nightmare, the “greasy hill.” Sometimes this happens because pumping stations are overloaded or treatment plants cannot process enough liquid. Regardless, it happens far more often than it should, indicating that many parts of the system—pipes, pump stations, treatment plants—are not equipped to allow sewage and stormwater to flow through the system.

In other words, the problem is not that water companies randomly choose to discharge wastewater. The problem is that they cannot control their systems. In fact, it’s even worse: they may not fully understand their system. This is a small but compelling example, and it goes back to the question we started with: the difference between the old Victorian combined sewer systems and the separate systems we should actually be installing. Conventional wisdom in the water environment is that we stopped building combined sewers years ago and that all new sewers built since the 1960s have been stand-alone systems. If you already know this, you know that this distinction is very important. Combined systems are basically guaranteed to overflow sewage; individual systems must be protected from their effects. But when we traveled around the country to visit some of the pipes we reported on, we struggled to find any of these ‘gold standard’ sewer systems in the UK.

We visited Denmark, and at a new site in Copenhagen, they not only separate rainwater from sewage, but also separate roof water from street water in a “triple separation system”. However, we haven’t even been able to find a common two-pipe split system in the UK.

This is even stranger because Water UK, a lobby group for water companies, says that of the 576,734 kilometers (358,365 miles) of sewers in England and Wales, only 96,193 kilometers (59,771 miles), or 17%, are combined sewer systems. They said the rest were separate drains. In theory, the British water system was very different from the Victorian model that Bazalgette decided on in 1856. But then things got murkier. Another estimate by the Danish Environmental Protection Agency shows that combined sewers actually make up 30% of all sewage systems, while another EU figure puts the figure at 70% of all sewage systems. No one can seem to agree – and no one can tell us how many homes have one system or the other. It’s one meaningless statistic after another. Things got even weirder when we finally asked British Water to help us find great modern wastewater treatment systems.

They told us that there are several towns with fully independent sewerage systems including Milton Keynes, Peterborough, Warrington and Telford. But when we checked the EPA data, it showed that all of those cities had overflows found only in combined systems—the dirty pipes that pour sewage into rivers when it rains (and sometimes when it doesn’t). ).

When we asked Anglian Water if there was a combined sewer system in Milton Keynes, they pointed to a map showing that although there are two overflow systems on the outskirts of the town, much of the town area is actually a separate system. But this is a rare exception.

In fact, the more we researched, the more it became clear that since Bazalgata, instead of modernizing the structure of the sewage system, we have actually doubled the old system. Although developers are now expected to install separate stormwater and sanitary sewer lines in new homes and buildings, in practice most developers simply point their lines to the same place: large combined sewer lines on the street. In other words, although general statistics suggest that UK sewerage systems are largely self-contained, the opposite may actually be the case.

Regulators, companies and politicians have a responsibility.

While it’s easy to blame the water company, it’s a complex problem that also has to do with the way we manage and regulate property development in this country. Going back to the fact that our urban spaces have evolved over hundreds and sometimes thousands of years. Planning laws essentially give any developer the automatic right to connect downspouts to main sewers, although they are sometimes cautiously encouraged to divert stormwater elsewhere. All in all, it’s a bit confusing. But, even more alarmingly, the more we research, the more we realize that these and other factors can make water systems as much of a mystery to the water utilities themselves as they are to us. In fact, there are currently no sewer system maps and clear records of where the pipes are, where they go, and what they carry. Just as no one wants to think about what happens when they flush the toilet, our water utilities have been happy for decades not to spend much time thinking about what’s going on below the surface.

Although it is now fashionable to claim that the UK is an exception, the situation is actually the same in most of Europe, where most have similar integrated wastewater treatment systems. The main difference is that most of these countries have not yet started collecting wastewater discharge data.

Caroline Worley of the European Environment Agency said: “This is a widespread problem. A lot of times people don’t even know where the [drainage] is. The first challenge is to map and find out where they are. “

In this respect, although UK data may be preliminary and unreliable, it appears to be slightly ahead of most European countries. It’s easy to blame the company for all of this. They deserve scrutiny for a variety of reasons, including how they manage their finances. In some cases – Thames Water is a good example – previous investors took on large amounts of debt and went out of business. Instead of committing to large capital investments, they were primed by making them dangerously dependent on capital from outside investors. But the responsibility should be shared more widely. The water regulator, Ofwat, is too slow to regulate these issues and is too keen to let companies not change the level of investment. Successive governments have been too focused on reducing water bills without trying to step in and encourage more spending on the system. The EPA was so slow to diagnose the sewage overflow problem that citizen environmentalists are now doing a lot of extra work to monitor local rivers when no one else is. All of this is before we even touch on the other important jobs that water companies do – not only removing dirty water from customers, but also delivering clean water to their homes and businesses. Britain is lucky this year: there is plenty of rain and no shortage of water. But more than thirty years have passed since the last time a new reservoir was built.

To be fair, this oft-repeated nugget isn’t as scary as it sounds: there’s been quite a bit of new reservoir capacity coming online in recent years, but most of it has been reservoir expansion and, in some cases, reservoir expansion. restoration. Conversion of the existing quarry into a water collection pond. However, as the climate warms, some parts of the country, especially in the south and east, could experience more drought.

Here again is the problem of underinvestment. For example, plans to create a national water network have been debated for decades. This makes some sense as many parts of the north and west of the UK have more water than they need. However, the country’s water supply system is still disrupted.

There is also a glimmer of hope. Anglian Water is building a water network covering hundreds of kilometers across the East of England. In London, the new Tideway tunnel is expected to catch 95% of the overflow in the Thames (although as you know it is a combined system and the occasional overflow cannot be avoided). The government says it has a new plan to encourage water companies to spend more on sewage systems.

But all these plans cost money – a lot of money. The total funding required for the modernization of sewerage and water supply is around 100 billion. GBP – Estimated cost of the HS2 scheme before it is scrapped.

This means future bills will be higher. Do customers think these higher bills are worth paying? Or will their dissatisfaction with the water supply system only increase in the coming years?

Environment Minister Theresa Coffey, who described the repeated cases of illegal sewage disposal as a “scandal”, said she would not comment on the size of the bill, but indicated that consumers might be willing to pay for improved systems.

“Any increase in bills can only be for new investments – not things that should have been done before,” she said. “People don’t have to pay twice.”

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And before you ask, it will be very expensive to replace the existing combined system (ie the Bazalgette model) with a separate system with two pipes (one for sewage and one for rainwater). Estimates put the figure at between £350bn and £600bn, which would make it the biggest infrastructure investment in history. This would involve digging up every road in the country, not to mention persuading every house to renovate its gutters and downspouts. So it won’t happen. But it carries a hard lesson that is not widely appreciated: We cannot prevent 100 percent of all sewage overflows.

Combined systems always have to release some effluent into rivers when it rains heavily. This is how our current system works.