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:

  • Evaluate if we are contributing harmful plastics to the water cycle
  • Establish their source and effective control measures to remove them

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.

UKWIR – the UK and Irish water industry’s research body – has commissioned the first study of its kind in the UK to develop a robust approach to sampling and detection of microplastic particles in the treated water cycle. This included accurately measuring the presence of microplastic particles in potable (drinking) water, treated wastewater and in the solid residues (sludge) produced by both the water and wastewater treatment processes. Please click here to view more information.


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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 - A holistic review of the impact of reducing the operation of sewer overflows on organic load to works, sludge production, carbon and GHG emissions..

Project Status - Project Commenced

Category - Wastewater Treatment & Sewerage

Currently the application of climate change to the DWMP and to LTDS has been carried out differently by companies. 

Companies require tools that take the UKCP18 climate model outputs and convert them into usable factors that can be applied within hydraulic models.  REDup has been created to enable the risk from climate change to be applied to hydraulic models.

The current REDUP tool provides information based on climate Projection RCP8.5.  Government guidance and regulatory requirements are now requesting evidence from Modelling to include Climate Projections for all climate scenarios.  Companies are being asked to produce this information with many more time horizons. The outputs of the tool need to consider how the data can be interpolated between years and whether the tool is capable of carrying out multiple year interpolation as well.

The tool also can produce outputs that are equally statistically valid for the same request.  Additional supporting information is required to explain this to our regulators.

We need a tool to comply with the current regulatory and statutory requirements and we need to work with our regulators during this project to capture any additional expectations for delivery as part of DWMP29 and PR29.

We need to prepare the tool to provide factors for more epochs that will allow us to react more quickly to direction from government through the planning process.


BQ06 - FOG Charging - Should foodservice wastewater charges reflect FOG content?.

Project Status - Project Commenced

Category - Wastewater Treatment & Sewerage

The project objective will be providing a ‘risk-based’ charging system for all FOOD SERVICE ESTABLISHMENTS (FSE’s – that include hospitality, commercial, restaurant and foodservice [both takeaway and seated]) kitchens based on the risk from FOG (fat, oil & grease + foodwaste) in the wastewater discharges from those FSE kitchens.

Ofwat to support the ‘risk based’ wastewater charging scheme in accepting that ALL kitchens that provide food in individual portions for consumption on or off the premises, will discharge wastewater that contains FOG & foodwaste. Currently FSE’s are billed in same way as domestic households, where there is an assumption that 92.5% of the clean water registered through the water meter is returned to the sewer as wastewater. No account is taken of the ‘risk’ to the public sewer from the content of that wastewater and consequently only the FSE’s that create blockages are considered a risk under Section 111 Water Industry Act 1991. In reality all FSE’s discharge FOG and billing based on that risk to the sewer and sewerage wholesaler operations.

FSE kitchen discharges are considered to be legally classified as  ‘trade effluent’, but to manage and enforce them as ‘full trade effluent’ customers would be logistically, physically and financially infeasible.
This project seeks to provide an alternative ‘half-way-house’ approach of a risk-based charging system that treats all FSE’s equally, regardless of their discharge location and size.
The FSE’s should be required to pay wastewater charges commensurate with their risk to sewerage wholesaler operations. If the risk is mitigated using certified grease management systems and supported by certified contractors for cleaning and maintenance, the cost of that risk is reduced.

The project objective would be to propose and recommend suitable FSE tariffs and appropriate percentage risk factors for FSE charging i.e., should the FSE with no grease management be charged 100% more (i.e., double the wastewater charges), but this charge can be mitigated back towards the normal 92.5% of the clean water used (by volume) by fitting effective and efficient grease management, recovering the maximum amount of FOG. The emphasis would then be placed on the ‘producer (polluter) pays’ as extended producer responsibility to drive behaviour change. This then supports the circular economy, zero pollution by 2040 and no CSO use.


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