Big question

BQ6 - How do we achieve zero uncontrolled discharges from sewers by 2050?



We are currently working on the approach to answering this Big Question, and more information will be given here soon.

The areas that this Big Question covers includes:

  • Reduce sewer blockages
  • Reduce overflows (escapes) at rising mains and pumping stations
  • Achieve integrated sewerage catchment management
  • Address sewer infiltration, excess surface water flows including flows from developments
  • Play our part in wider flood management
  • Support the industry’s 21st Century Drainage programme of work

Once we understand where the gaps are, we will produce a route map – this is a plan as to how we will answer our Big Question.

The route map will have a number of key elements. At the top will be our Big Question and then we will look to see what Outcomes we need from the research programme -if we can achieve all these outcomes we can answer the Big Question. This is the stage we are currently at for this Big Question.

The next stage will be to think about the key benefits we want the research projects to deliver to meet these outcomes.

Following this, we will plan the research projects to help deliver the benefits.


See All Projects  



BQ06 - Treatment Options for Storm Overflows.

Project Status - Project Completed

Category - Collection Systems

In order to deliver the required improvements to progressively reduce the adverse impact of storm overflows as detailed in the Environment Act, opportunities to treat overflows need to be further explored including their application, costs and benefits.  


BQ06 D01 - Learning and recommendations from customer behaviour campaigns on blockage reduction.

Project Status - Project Completed

Category - Sewerage

Each year water companies spend millions of pounds on responding to and resolving problems caused by the disposal of inappropriate materials into the sewer network. It is estimated that 40-50% of all sewer blockages are caused by wet wipes with a further 15-20% been caused by FOG in some water companies. 

Together a more than half of all blockages are caused by the disposal of inappropriate materials making this one of the single biggest challenges in achieving zero uncontrolled discharges by 2050. 

To try and combat this issue each company has their own customer behaviour campaigns aimed at blockage reduction. These campaigns include a mixture of techniques from social media, radio & print adverts to more targeted interventions by network protection teams. Each campaign usually has a strap line associated with it. 

•    Keep it Clear” at Anglian Water.
•    “Stop the block” at Welsh Water.
•    “Think sink” at South West Water.
•    “Bin it don’t block it” at Thames Water and Yorkshire Water.
•    “Dwayne the Drain” at Northumbrian Water.
•    “Let life flow” at Wessex Water.

Despite the numerous campaigns by all the associated companies very little learning is shared at a national level. 


BQ06 B04 - Modelling Sewer Inlet Capacity Restrictions.

Project Status - Project Completed

Category - Sewerage

Develop a methodology to better represent how inlet restrictions are embodied within sewer modelling to improve our understanding of flood risk during severe rainfall events.


BQ06 Understand the long term costs and wider benefits of Surface Water removal and SuDS to tackle sewer flooding and storm overflow operation.

Project Status - Project Commenced

To tackle storm overflows and sewer flooding, the removal of surface water from the combined sewer system via SuDS represents a potentially more sustainable alternative to traditional grey infrastructure and has the potential to deliver wider benefits to the environment and society including longer term flood resilience. 

Initial costs and benefits appraisals (including carbon estimates) for SuDS through the Storm Overflow Evidence Project and Drainage and Wastewater Management Plans have indicated however that SuDS could be potentially higher in both cost and carbon. 

Because there are relatively few examples of the whole life costs and benefits of retro-fitted SuDS delivered by the Water Industry this research aims to further develop our understanding of the initial capital costs, long term opex costs,  and whole life benefits. 
It will also deliver tools that can be used for planning purposes and to influence regulation and policy. 


Infiltration detection.

Project Status - Project Completed

Category - Sewerage

There are several methods recognised to detect infiltration (CCTV, Electroscan etc) but all appear to have shortcomings that prevent them being as effective as is needed. Infiltration seems to be an intractable problem for several companies in the south of England (and others to a lesser extent) and can only be remedied where measurable (short of wholesale replacement/relining).

This suggestion is to engage with universities/academia to suggest and pilot alternative technologies