Understanding sewer corrosion

Everyone knows that as far as sewers go they are usually ‘out of sight and out of mind’. But as anyone who has been personally involved in a sewer malfunction it is a mortifying and scary experience. It shows us how thin is the membrane that protects us from reverting to medieval levels of public health. For the UK water industry, responsible for maintaining the country’s largely Victorian sewer infrastructure, it’s also clear that this is one of the most neglected and costly of their responsibilities since being out of sight also means it is difficult to ascertain the local condition of these vital conduits often until it’s too late.

How exciting is it therefore that work done by Mark T. Hernandez of the University of Colorado, Boulder, reported in Environmental Science & Technology and described in a recent issue of the Economist (14 June 2014) applied the latest bioscience understanding and sensor technology to described a methodology to warn when and where sewers may potentially fail.

Prof. Hernandez has been looking at the gases associated with concrete corrosion in sewage pipes. He has focused on two in particular, hydrogen sulphide, and carbon dioxide. Although hydrogen sulphide contributes strongly to the odour in sewage it does not appear to directly affect pipe decay. However the presence of particular bacteria will under certain conditions convert it into sulphuric acid which does damage pipes!

Photo: Graphic from the article by Hernandez and his colleagues in Environmental Science & Technology.

Photo: Graphic from the article by Hernandez and his colleagues in Environmental Science & Technology.

Studies showed that sewage above areas of pipe corrosion were, as would be expected, highly acidic (pH 1). The biodiversity of the bacteria in that region was also much lower than above areas where there was no damage. In this impoverished ecosystem a bug that turns hydrogen sulphide into sulphuric acid predominated showing how the corrosion process becomes increasingly aggressive. Importantly in the area of the corroded pipe, gas measurements showed not only high hydrogen sulphide concentrations (above 100 ppm) but also very high carbon dioxide levels (10,000 ppm).

Analysis based on these results should lead to an extremely accurate diagnostic test as to where damage is occurring. We hope water companies will use this scientific result to monitor their assets rather than wait until there is a catastrophic structural collapse when there is no recourse other than to digging holes.

Roger Ford

Water MOOC launched!

Today our Water Supply and Sanitation Policy in Developing Countries MOOC launched on the Coursera platform. It’s been developed by the University of Manchester and is endorsed by the Global Water Partnership.

Photo: Prof. Dale Whittington and I from one of our water MOOC videos.

Photo: Prof. Dale Whittington and I from one of our water MOOC videos. Filmed at the University of Manchester.

We’re very excited, and a bit taken aback, that our launch day analytics suggest we’ve got over 12,000 learners enrolled, coming from 182 different countries:


It’s superb that 41% of our learners seem to be coming from the so-called ‘emerging economies’. Hopefully that means we have people enrolled who would not normally have access to a course like this.

We’re also curious to know what impact our materials might have on people’s ideas and professional practices around in the world, both now and perhaps in years to come. The material in this MOOC normally only reaches a handful of people each year. This is the first time such large numbers will engage with it.

We really hope people will find it useful, informative and challenging; lively discussion forums are a part of all MOOCs, so I guess we’ll soon see if they do!

The water MOOC course is going to run for six weeks. We’ll address global water and sanitation infrastructure coverage, political economy and corruption issues, supply-side issues including costs, demand-side factors, climate change and health and non-health outcomes, and sequences of decisions over time that create and lock-in what we’ve called ‘water development paths’. We’ve also got a series of interviews with guests, e.g. with former UNICEF Water, Sanitation and Hygiene (WASH) chief, Clarissa Brocklehurst:

Photo: Dale talks with former UNICEF WASH chief, Clarissa Brocklehurst.

Photo: Dale talks in our MOOC to former UNICEF WASH chief, Clarissa Brocklehurst.

Remember you can still sign up to take this water MOOC, and it’s completely free of charge. Please do come along and join in!

Duncan Thomas

Activated sludge centenary

A fortnight ago I was fortunate to take part in some of the 2014 centenary celebrations of the 1914 invention of activated sludge in Manchester. The day before the centenary conference we kicked off with a fascinating – and not quite as smelly as expected – visit to Davyhulme sewage works kindly organised by site owners, United Utilities.

The 1.2 million population equivalent Davyhulme site is so large that UU had laid on a bus for the tour. Our first stop was at the inlet screenings area, complete with sample ‘rags’ in a wheelbarrow (‘not all toilet paper’, our host stressed):

Photo: Covered screens for one of the treatment lanes at Davyhulme sewage works.

Photo: Covered inlet screens for one of the treatment lanes at Davyhulme sewage works; typical screened out ‘rags’ shown in the wheelbarrow in the foreground.

Photo: Display board at the inlet screen, one of several prepared by UU for the Centenary; the inlet screens are marked number 1 on this site map.

The display board told us that two of three main sewers feeding Davyhulme from parts of Manchester are huge – one is a 10ft gravity sewer; the other is 13ft in diameter. The plant can also treat up to 714 megalitres a day and has an additional 105 megalitres of storm tank storage (that were originally primary settlement tanks).

Our guide, Lee Donnellan, at various points during the tour, showed us samples of the flow through the plant, like this one from the works inlet:


Photo: Bottled sample of the sewage from the inlet lane in the background.

Photo: Bottled sample of the sewage from the inlet lane you can see in the middle ground.

Then it was time to see the activated sludge tanks, which sit next to a much newer BAFF (Biological Aerated Flooded Filter) plant at Davyhulme:

Photo: The activated sludge process in action at Davyhulme.

Photo: The activated sludge process in action at Davyhulme (the novelty that was published by inventors Ardern and Lockett in 1914 was to use certain ‘micro-organisms suspended in the sewage without the need for large filter beds’ as described in the display board shown below).


Photo: Display boards describing the invention and operation of the activated sludge process at Davyhulme.

Photo: UU’s display boards describing the invention and operation of the activated sludge process at Davyhulme.

Lee then showed us more sewage samples taken at various points as they pass through the works, right up to the stage of cleaned, fully treated effluent that is discharged from the works:

Photo: Samples of the sewage sludge from inlet to discharge. The third picture is from the activated sludge tanks.

Photo: (L to R) Samples of the sewage from inlet to discharge. The third sample is from the activated sludge tanks.

We also had a quick look at the BAFF plant, installed at Davyhulme in 1999 according to the display boards to address ammonia levels that were harmful to aquatic life in the Manchester Ship Canal:

Photo: Display board about the BAFF plant at Davyhulme.

Photo: Display board about the BAFF plant at Davyhulme.

Photo: Housing for the blowers to aerate the BAFF plant at Davyhulme.

Photo: Building housing the energy-sapping air blowers that aerate the BAFF plant at Davyhulme.


Photo: Treated flow leaving the BAFF plant at Davyhulme ready for discharge into the nearby Manchester Ship Canal.

Next up was the £100 million sludge recycling plant that was finished at Davyhulme in 2013. At the time it was the world’s largest thermal hydrolysis plant; it’s now the 2nd biggest due to the fact that a larger one has been commissioned in Washington, DC.

Photo: Panorama pics of the very large thermal hydrolysis plant at Davyhulme, treating sludge at high temperature then enabling biogas production for energy recovery.

The size, noise, heat and rather concentrated smell of this thermal hydrolysis area is hard to convey with pictures alone! Some members of the tour party also had concerns about this plant’s longevity given its operational stresses. At present though it seems like a laudable effort to get renewable energy out of the works and higher quality sludge for application to land.

Photo: Odour control at Davyhulme.

Photo: Odour control at Davyhulme.

There was an emphasis on continuous – and very expensive – development of the site throughout the tour. Notably a £200 million investment is now starting. This is to address the age, condition and performance of large parts of the historic site, given that much of it has been in place and not radically re-vamped for decades. There was also a forward-looking emphasis on what the next 100 years might hold – a theme that carried over into the actual conference the following day.

Photo: Map of the 100 square km area covered by Davyhulme sewage works.

Photo: Map of the 100 square km area covered by Davyhulme sewage works.

Photo: Display board explaining another £200 million investment is now starting as part of the plant's next 100 years!

Photo: Display board announcing another £200 million investment to launch Davyhulme’s next 100 years!

The conference began with some audience participation led by Prof. James Alleman in the chair. First he asked the audience how many of them had actually worked on an activated sludge plant; most hands went up (not mine!) showing that it was really a community of practitioners at the event. Second, he asked about lengths of service and age from the audience. This reached people in their eighties whose relatives had been based at Davyhulme in early years, and people with well over 30 years of service in the field of activated sludge:

Photo: Prof. Alleman marshalling a remarkable series of shows of hands about years of service in the field of activated sludge.

Photo: Prof. Alleman marshalling a show of hands for the audience’s impressive years of service in activated sludge.

A number of points struck me during the conference presentations:

  • This was a rare gathering of a niche community of dedicated people from around the world who have devoted decades of their lives to the study and improvement of a world-spanning treatment process;
  • It’s important to celebrate taken-for-granted, flush-and-forget, no doubt unpalatable to most, but nevertheless vital, world-changing technology and system innovations like this;
  • There’s been a mixture of tradition and conservatism interspersed with a few bursts of energy and innovation in the activated sludge area – seemingly pretty consistent with our general view of innovation in the water sector here; and
  • An interesting range of exhibitors (mainly suppliers) at the conference exemplified continued invention and innovation in the sector, although some had had familiar problems in getting any large-scale uptake from UK water utilities.

One surprise for me from the conference content was about the UK/US litigation that had ensued very shortly after the invention of activated sludge. It didn’t slow the process’ rapid adoption, remarkable given that this legal action could have been barrier enough let alone the fact that this was also a time of world war. Dr Nigel Horan told us how the original inventors and collaborators for activated sludge – particularly Weizmann and the Mumfords at the University of Manchester, Ardern and Lockett at the Manchester Rivers Department, manufacturers Jones and Attwood, and ‘knowledge broker’ Gilbert Fowler – had fundamental disagreements about intellectual property that led to various court cases.

Photo: A historical shot of Davyhulme from the conference displays.

Photo: A historical shot of Davyhulme from the conference displays.

There was also nostalgia during some presentations for apparently lost ‘golden ages’ of research and exploration in the water sector, of the sort that were seen to be no longer possible due to post-privatisation competition, among other things. One example quoted by Dr Horan was the remarkable 17-year long investigation of sewage options during the 1898-1915 Royal Commission on Sewage Disposal. Clearly no such modern effort of this scale exists; there was a feeling at the conference that this may be holding the industry back in the face of the many challenges it faces (e.g. carbon footprint, energy and chemical dependency, affordability, climate change resilience).

Overall though it was a great event. I really enjoyed my time on the tour and at the conference. I know the sector has a habit of talking more about innovation than doing it, but this was I feel a worthwhile celebration of fundamental change. Hopefully reflection upon its circumstances and consequences may spur similar improvements by the time this band of enthusiast engineers and scientists gather again (albeit the younger ones!) for the next milestone in the history of activated sludge.

Duncan Thomas

Water MOOC launching 26 May!

In the last few days we’ve confirmed a 26 May launch date for our first ever Water Supply and Sanitation Policy in Developing Countries MOOC (massive open online course). If you visit our Coursera page you will see this:


All you have to do is click on the blue bar, ‘Join For Free’, and you can now enrol right away!

Our MOOC is coming out of the University of Manchester and has been endorsed by the Global Water Partnership. Course leader Dale Whittington and I are really looking forward to it, and we’ve been busy preparing materials, as well as trying out how we both look on film (these pics are from the last few weeks):




We’re lining up some exciting special guests from around the world of water for the course too; details to follow once we’ve got them all recorded.

It’s a fascinating (and rather busy!) time but we hope to have a few more updates as we move even closer to the launch date…

Duncan Thomas

Warmer, wetter winters ahead?

Following on from my last post about the stormy end to 2013 in the UK, the past month or so has continued this disturbing trend and some regions have had atypically high amounts of rainfall:

Photo: Rainfall for Jan 2014 in the UK compared to 1981-2010 average. Source: BBC / Met Office.

Photo: Rainfall for Jan 2014 in the UK compared to 1981-2010 average. Source: BBC / Met Office.

Photo: The Jan 2014 UK rainfall has been the highest since records began over 100 years ago. Source: BBC / Met Office.

Photo: The January rainfall in SE and central southern England reached the highest levels for the month since records began over 100 years ago. Source: BBC / Met Office.

On top of these intense and heavy rainfall patterns, January was also an unusually warm month for almost all the UK:

Photo: January temperatures compared to the 1981-2010 average for the UK. Source. BBC / Met Office.

Photo: January temperatures compared to the 1981-2010 average for the UK. Source. BBC / Met Office.

Most scientific researchers these days rightly do not attempt to attribute specific weather events or sequences of events directly to climate change (because of unknowns and knowns in modelling approaches, and due to the variety of overlapping weather-affecting cycles of differing lengths that are known about).

The BBC’s environment analyst put it this way, ‘The jury’s still out on whether humans are to blame for extreme weather‘. Nevertheless what we’ve seen in the UK in the past few months I believe is at the very least highly illustrative of one possibly reality behind what researchers actually mean when they talk about projections of ‘warmer, wetter’ winters in the UK if and as the climate changes along the path(s) we currently believe are possible. In spite of some potentially positive impacts predicted from climate change, e.g. for certain types of tourism and agriculture, I think the range of devastation and disruption played out in the UK over the past weeks is a challenge to anyone who might suggest that ‘warmer, wetter’ winters – with associated characteristics of more intense, heavier rainfall events – are something to welcome without reservation.

There’s also the other attribution to human behaviour issue here, which is the role of man-made floods and water management and planning. George Monbiot summed the issues up very well (see also the side-box of this BBC story). Monbiot scathily attacked the misdirection of public funds that have increased not decreased resistance and resilience to flooding, e.g. by canalizing rivers and thereby accelerating flood water flows in places:

‘Vast amounts of public money – running into the billions – are spent every year on policies that make devastating floods inevitable. This is the story that has not been told by the papers or the broadcasters’

TV and print media seem to be catching up, it must be said, in the wake of recent weather events – and Monbiot’s post. One example that caught my eye was the recent C4 Dispatches called ‘Floods: Your Money Down The Drain‘:

Photo: C4 Dispatches documentary episode about the recent floods, their foul flooding impacts, and water sector investments in the UK.

Photo: C4 Dispatches documentary episode about the recent floods, their foul flooding impacts, and water sector investments in the UK.

The reason that it did was the team at October Films that made it had contacted me several times over the past few months. We had some very interesting discussions about issues of how and where the UK water industry has and hasn’t invested to help or hinder problems of foul flooding from sewers, and the general incremental, conservative attitude of the sector to new approaches and new technologies. (Sadly I didn’t end up being filmed, for a number of reasons; still I wonder if my name appears in any acknowledgements in the credits? It seems bonkers to an academic not to cite one’s sources, but we’ll see what the norms are in the media world when I’ve had time to watch the programme.)

The coming weeks and months will see if there’s any policy shift in response to these criticisms, to the scale of impact in Wales, SW England, and for planned job cuts at the Environment Agency given that it has clearly been operationally stressed by recent events (here’s hoping its premium rate floodline will be dropped though).

Duncan Thomas

A stormy end to 2013

Hot on the heels of a pretty lousy 2012, weather-wise, this year is ending up in a very stormy, flood-ridden state indeed – and sadly has created misery for many here in the UK. A few days ago, just as I was about to travel for an event with one of the choirs with which I sing, the Environment Agency’s flood alert map looked like this:

Photo: The EA's rather alarming-looking flood alert map for England and Wales on 27 December 2013

Photo: The EA’s rather alarming flood alert map for England and Wales on 27 December 2013

I can’t say I’ve ever seen it look that bad before. The build up had been storms driven by a very energetic jet stream that drove extreme weather just before Christmas Day leaving thousands of homes without power over Christmas and energy companies struggling to reconnect them for several days afterwards. Today storms have been hitting again, in Wales and in Scotland.

This winter-time rain comes hot-on-the-heels of last year’s incredibly wet year, the peak of which the Met Office summarised last year like this (for the summer/July):

Photo: The Met Office's data showing how much wetter than average the summer was last year (2012).

Photo: The Met Office’s data showing how much wetter than average the summer was last year (2012).

Last December was wetter than the 1961-1990 average (by 200% in places) but with all the recent storms I wonder how December 2013 is going to look in the upcoming Met Office summary? The data is not yet there, but we should know shortly. My bet is it won’t look good.

The interdependency between water and energy infrastructure, and the role of UK energy companies in particular, is likely to be a focus point in the coming months, with compensation demands and a general feeling that companies ‘let customers down‘ pervading much of the recent news coverage. Hopefully there will be some integrated thinking about resilience to extreme weather in all of this – particularly as there are apparently more storms still on the way and a risk of more damage and disruption.

Duncan Thomas

What price regulating?

Earlier I saw a BBC story on the depressing news that household energy prices in the UK look set to continue to rise above inflation for the next 17 years. This is according to a new report by the National Audit Office. (NB. The full NAO report looks generally at the impact on household bills of the estimated £310 billion budget needed to implement the 2012 update of the Government’s 2010 National Infrastructure Plan.)

This all started me thinking about the UK water sector’s long-term household water bills. Looking back of course the trend has been largely upward. For England and Wales there’s been above-inflation increases from 1989-2000, a one-off cut in 2000, a decade of further rising prices, and now more or less flat pricing (NB. this is 2009 data with projections; if I manage to find an updated chart I’ll put it here instead):

Picture: Average household bills for England and Wales 1989-2015. Source: Ofwat.

Picture: Average annual household bills, England and Wales, 1989-2015 (not adjusted for inflation). Source: Ofwat.

Looking ahead, short-term we’ve heard strident calls both by the coalition and Labour for action on rising water bills and worsening affordability – coinciding with the ongoing Thames/super sewer/blocked 8% price rise fiasco (more on that in another post!).

Probing out a bit further signposts of future price directions can also be found in the post-2009 Price Review, ‘strategic direction statements‘ water companies are now required to produce (these ‘provide a 25 year context for the companies’ five-year business plans‘, state the objectives of water companies’ ‘long-term charging strategies’, and address ‘how they plan to achieve these and the implications for bills‘). Quickly going through a few of them, for the bigger companies – and noting this was hampered by dead links on the Ofwat page and lousy searching functionality on water company websites – hunting around for the word ‘bills’ (comes up a lot!) reveals some of the following outline visions of future water pricing:

  • Anglian state an aspiration ‘to deliver our strategy while limiting bill increases to an average of one per cent above inflation over the long-term‘ – that is, unless ‘major investment‘ becomes needed ‘to adapt to the impacts of climate change.’
  • Severn Trent (whose statement is under revision it seems) loosely propose they’ll ‘keep costs and bills no higher than they need to be‘ but then helpfully do separate out potential cost increases by 2035 – i.e. from water quality improvements (+£3 on bills by 2035), avoiding supply interruptions (+£15), leakage reduction plans (+£5), increasing the rate of metering (+£3), water efficiency plans (+£1), increasing supply capacity (+£9), added costs of supply pipe adoption (+£8).
  • Thames look decidedly defeatist/pessimistic in this company, bleakly stating that, ‘in order to meet future challenges, we will have to make substantial additional investments, which will mean that bills will need to increase‘ (their position may be shifting on this!). At the same time they do address affordability, suggesting that ‘[t]hroughout our 25-year plan, water charges are expected to remain below 1.5% of disposable income on average.’
  • United Utilities present a rather vague, non-binding strategy to ‘strike the right balance between keeping bills affordable whilst ensuring our water and wastewater infrastructure receives the investment it requires.’
  • Wessex also are non-committal in their aim to ‘demonstrate to our customers and others that we are playing our part in improving resilience and keeping bills down … at the level customers are in general willing to pay.’
  • Yorkshire only talk about ‘[p]roviding the lowest possible prices‘ and instead focus on their proud claims that ‘[t]arget-setting and innovation have been the building blocks of our success in keeping price increases to no more than inflation in respect of our expenditure on operations and capital maintenance‘ whilst laying blame at the door of ‘[i]ncreases in tax and essential environmental legislation as ‘key drivers of above-inflation price increases for our customers in the past.

Delving beneath these – largely vague – statements about future price directions, I’d like to talk about another perhaps significant factor. This is the as yet unknown impact of the recent departure of Regina Finn from Ofwat. I baulk, of course, at focusing too much on particular, individual personalities. I’m also aware Ofwat changed from a Director General-model to a board structure in part to mute this aspect (and to, no doubt, bring in more and fresher views into high-level decision-making). Nevertheless, after being thoroughly unimpressed with Ofwat for many years, I find myself realising that it was during Ms Finn’s tenure as chief exec that arguably the most significant moves towards regulatory reform and better longer term planning have been started. I see this period very much in the same vein as set out in Ms Finn’s own words, from her resignation press release, as being when Ofwat began to lay ‘the foundations for a new model of regulation in which water companies have to listen to their customers and deliver a step-change in their performance‘.

We’ve got long-standing concerns of course about the heavily entrenched culture of conservatism and incrementalism across the UK water sector. Above and beyond any actions by Ofwat alone, much will no doubt rest on whether a new customer-focused, more proactive culture actually materialises in the coming years. Sadly, scanning through reported opinions during the build up to, and in the wake of Ms Finn’s resignation, I think there remains cause for concern.

What do I mean? First, a few caveats. For starters, it’s not uncommon in regulated utility sectors to have emphasis upon – and even demonisation of – individual personalities. It’s a price one pays leading a regulatory body, and sadly some vilification comes with the territory. Second, honestly I can’t accurately assess the veracity of reported internal goings-on in Ofwat, including how its staff perform and how its working environment operates. I’m on the outside looking in, including when I read rather stark remarks about 49% of staff reporting in an internal survey that they had no confidence in Ofwat’s executive team, and only 19% reportedly confident (compared to a 39% civil service sector average).

I can only look externally then at what I see as processes and principles at work. To do so, a recent paper on regulatory capture by Ms Finn (and Simon Less) actually proves very handy. Specifically, when I read criticisms that proposed regulatory reforms involved too much ‘uncertainty’ and ‘risk for investors’ that would increase the cost of capital and drive up household water bills, I hear a clear call for the regulator ‘to take decisions that are biased in favour of the interests of the industry they regulate rather than the customers or wider society on whose behalf they regulate‘ – i.e. regulatory capture by industry, as Finn and Less define in their paper (where this quote is from). And yet it’s not a linear causal link between regulatory reform and eventual household bills. We know, there’s a lot that water companies could do to innovate to mitigate various cost pressures. And they are, largely, not doing innovating to do so. Against this known background then, lazily citing ‘risk to investors’ risks sounding simply like carefully crafted scaremongering.

When regulatory staff though, again as quoted in Utility Week, also apparently appear unwilling to accept uncertainty as an inherent part of regulatory reform, to my eyes, they risk misrepresenting an essential regulatory role – i.e. to provide a strong, independent challenge to the vested interests and power of a monopoly sector. I mean, come on, will I really live it up to water companies and their investors to offer independent scrutiny and to have my best interests at heart, above and beyond shareholder returns? No, the regulator has a crucial role to play here, on my behalf. And if its independent challenge process takes several rounds of heated to-ing and fro-ing between regulator and regulated, and involves at least some risk exposure for investors that have been largely used to milking a ‘cash cow’ in deference to the sector’s laggard climate change resilience and sustainability performance (and ‘industrial scale’ tax avoidance), then so be it!

I must reiterate again though that I don’t know if independent challenge has been the motivation or whether, again as quoted in UW, there has been a seemingly petty ‘desire to win a fight with the water companies rather than wanting what is best for its stakeholders‘. All I can say is that I expect the regulator to challenge vested interests and business-as-usual practices. The UK water sector is notoriously inward-looking. It largely isn’t exposed to competition or to best practice challenges from other countries or other sectors. If its regulator(s) provides no challenge, who’s left? If a regulator falters to me it broadcasts that it’s itself become ‘captured’ – this time in ‘its own historic way of doing things‘ and ‘particular regulatory processes that it has spent time and effort honing‘ – and may not be asking itself if ‘[w]hat may have worked in a previous period is not necessarily best approach today‘? (Quoting Finn and Less again here.)

With much of the new regulatory framework already in place, perhaps my pessimism is unwarranted. Regina Finn herself, now departed from Ofwat, but just a few days ago having joined new regulatory and policy consultancy, Lucerna Partners (and other utility-related things) may also not just give up on the promise of a more innovative, sustainable and customer-focused UK water sector. Being outside of Ofwat I also don’t yet know where new chief exec, Cathryn Ross may aim to take matters (as an aside, it’s heartening to see another high-level female appointment in a largely male-dominated industry here).

Returning to where I started, and thinking about long-term water price directions, sadly I’m still not optimistic. The resurgence of entrenched, almost vitriolic resistance to change around regulatory reform and Regina Finn’s resignation have not been edifying. For now then, who can predict the direction of long-term water pricing in the UK. Perhaps it will, like energy, be locked into many years of above inflation price increases?

Duncan Thomas