87 Sewer blockages and CSOs

The picture was inspired by a clue in the Guardian crossword of “Sewer obstruction (7)”.? The answer was, of course, fatberg.? This was on the same day that I spotted an announcement from the UK Government on allowing unlimited civil penalties for pollution.? This included a reference to sewer blockages and overflow discharges.

I discussed in Episode 49 the government announcement of plans to allow unlimited civil penalties for breaches of environment permits.? This was generally reported as, “Water companies could face unlimited fines for dumping sewage”.?

I pointed out that:

• It didn’t just apply to water companies, but to all polluters.
• Fines from a prosecution for pollution were already unlimited for serious cases.? This change to civil penalties would therefore only affect non-serious cases that were serious enough to warrant a penalty of more than ￡250?000.? You could probably count those on the toes of one hand.
• The plan was therefore more ornament than useful instrument.

Anyway, on 11 December 2023, the new Secretary of State for Environment, Food & Rural Affairs, Steve Barclay, announced that these changes had come into force.? The press release did point out that a wide range of potential organisations could be affected by the change.

• Breach of permit conditions from sites that discharge into rivers and seas – for example from sewage treatment works and permitted storm overflows.
• Illegal discharges to water where there is no permit such as in the event of agricultural pollution from slurry stores.
• Illegal waste offences, such as from illegal scrapyards or unpermitted waste management facilities.
• Permit breaches from manufacturing industries and power stations which contribute to air pollution.

It is good to see that as well as being aimed at water companies, agriculture, the waste sector and industry are also accepted as being in scope.? However, the announcement was accompanied by letters from the Secretary of State to the Environment Agency and to water companies that reverted to type by focussing on the water companies.

The letter to the Environment Agency said:

“Water company performance, specifically, is below the standards we should expect. ?The public rightly expect that I will hold not only water companies, but also their enforcement agencies to account, and that is one of my top priorities in this role. ?I expect significant improvements in the regulatory oversight of water companies.

I look forward to seeing your use of these new powers to ensure that polluters are held to account and are appropriately deterred from breaking our environmental laws.”

This despite the fact that agriculture is the most significant cause of watercourses not achieving good standard.

The letter to water company Chief Executives said:

“Tackling storm overflow sewage discharges is a key priority for both the Prime Minister, myself and, most importantly, the public”

As I have said previously, sadly no politician ever lost votes by kicking the water companies as hard and as often as possible.

However, the next part of the letter was much more interesting and does not seem to have been widely reported.

“We expect companies to outline the spill reductions that you will secure in the next twelve months as a result of an enhanced maintenance programme.? This is a core legal requirement that you should already be delivering.”

It is interesting that this is included in the same letter as the increase in civil penalties.? Is this implying that a discharge due to a “Sewer obstruction (7)” is the fault of the water company and will therefore incur an unlimited civil penalty of more than ￡250?000. ?Ouch.

So assuming that water companies take this seriously (I think they should) what can they do to respond?

EDM data

It is claimed that 100% of storm overflows in England and Wales are now fitted with Event Duration Monitors (EDMs) that record when they are spilling.? Most although not all of these will provide live data.? There is therefore a source of data for when an overflow is spilling when it shouldn’t be due to a blockage.

There are systems available that use analytics and machine learning to compare rainfall data and data from adjacent EDMs to identify anomalies.? Some companies are using a different approach of live running of detailed sewer models to identify anomalies.

The key thing is how you react when an anomaly is identified.? In the current political atmosphere this should be quickly and effectively so that you can fix any problem before it causes reputational damage.

Any overflow that has had a blockage should be put on a routine proactive cleansing programme and the frequency of cleaning adjusted to prevent future blockages.

Other locations

But the Defra target is not necessarily restricted to spills from overflows.? What about spills from manholes adjacent to watercourses due to blockage in downstream sewers.? There will not be any EDM data here.

For watercourses that are particularly sensitive to spills then nearby sewers should perhaps have level monitors installed to identify the build up blockages even though this is not required by environmental permits.?

There should also be a programme of proactive cleaning across the sewerage system based on the history of previous blockages and on the landuse of the upstream catchment.? Some companies developed such programmes 30 years ago and I believe are still using them.? Do they need review, are they still effective, are the thresholds for action still appropriate.

For particularly critical locations it may even be appropriate to have automatic flushing systems to avoid blockage formation.? These were first used over 100 years ago and are coming back into fashion.

Customer education

Blockages form when the conditions in the sewerage system are conducive to them and where the sewage contains material that is prone to forming a blockage.

A key activity is therefore customer education to not discharge fats oils and grease and solids down the drain.? The water companies are already doing a lot of this through adverts, social media, schools outreach and even door to door campaigns, but more is probably needed.? How about another documentary dissecting a fatberg as discussed in last week’s blog?

A key focus of water company action on the discharge of unsuitable material into the sewers is to campaign for a government ban on the sale of wet-wipes that contain plastic and so do not break down in the sewers and build up to form blockages.? A?consultation?on a UK wide ban on wet wipes containing plastic was started on 14 October 2023, but it is not clear if and when it will come into force.? Now that Steve Barclay is championing reduction in overflow spill due to blockages maybe he will push this forward more quickly.

Pumping stations

The target for reducing spills due to lack of maintenance could also apply to pumping stations and their rising mains.? These suffer from the same problems of blockage with the same solutions of monitoring, proactive cleaning and customer education.? They also potentially suffer from mechanical and electrical breakdown.

Pumping stations are in general monitored much more intensely than the rest of the sewerage system which should provide advanced warning of something going wrong.? However, if anything, there may be too much information so that it is difficult to identify the critical signals.? Again a machine learning system can help to find the real problems so that they can be responded to quickly.? More monitoring of discharge pressure in rising mains would be useful to identify poor pump performance and rising main failure.

Conclusions

So yes, perhaps all of this is a core legal requirement that the companies should already be delivering.? But is there enough budget in the Ofwat determinations to cover it all?? Or are these good housekeeping measures the things that get squeezed out when budgets are tight?