The CSO Challenge

Response and maintenance solutions to reduce the impact from, and expand the capacity in, your combined sewer overflow infrastructure.

We know that the issue of combined sewer overflow use is firmly in the public consciousness right now with continued and sustained negative media coverage. Your customers and your stakeholders are demanding action.

The Government has rightly responded with stricter legislation with a duty on water companies to publish data on storm overflow operation on an annual basis, and the Environment Agency (EA) is issuing more and increasing fines for misuse.

We know that this AMP cycle budget does not cover capital expenditure on new CSO infrastructure projects, so you need to be creative with the budget you have.

What the law says

The Sewage (Inland Waters) Bill means it is now a legal obligation of the water companies to publish data on storm overflow operation on an annual basis by implementing monitoring devices on all assets by 2023.

The EA requires a rolling schedule of storm overflow survey and maintenance with poorly performing sewers marked out for investment and improvement.

Assess and understand

Assess – evidence - resolve

You need to first determine if your CSO use is as bad as the media suggest while helping the public and media understand more. We help you build a business case based on scientific data to help call for more investment where there are environmental impacts.

Our assess – evidence - resolve approach helps you to understand your underground infrastructure and volume challenges.

This supports the SOAF assessment process and ensures you remain compliant with monitoring requirements.

It also helps you to prioritise the assets most in need of unblocking or repair as well as those assets at greatest risk from extreme weather to build a maintenance schedule based on scientific risk data.

We also have specialist underground monitoring and expertise of complex assets such as syphons running under rivers and roads through our group company Oneline.

If these assets collapse or crack they can be complex and costly to repair. Our regular inspections will determine the integrity of the asset to ensure a suitable monitoring programme is in place to identify and remediate issues before they become too costly. 

Our OS19X qualified team map your underground infrastructure and identify the exact repair location in a CCTV survey.

Assess and monitor

Assessing the status of the ecology in water bodies is essential in understanding the response of ecological system to water quality and water quantity.

Our ecologists are able to assess a wide range of ecological indicators such as aquatic macro-invertebrates, macrophytes, diatoms, plankton and fish.

Our integrated approach, links aquatic ecology to habitat availability, flow and water quality.

We assess a range of habitats including rivers, lakes, ponds, canals, and tidal or marine environments.

  • Environmental impact assessment surveys
    • Water sampling analysis and reporting
    • Macro invertebrate surveys analysis and reporting
    • Fisheries surveys analysis and reporting
    • Upstream catchment surveys SOAF Assessments
    • Installing and reporting event duration monitors
    • Support with SOAF assessments
  • Water quality monitoring
    • Real time remote water quality monitoring
    • Real time effluent monitoring and data report
    • Shoreline assessments and bathing water sampling
  • CCTV underground infrastructure mapping to create a priority list for improving the most harmful assets

Maintain and expand

Improve operational efficiency

Adhere to EA regulations by prioritising maintenance works on the worst offending assets and maximising your existing CSO assets using the information gathered in the assessment.

We find that in our routine drainage PPM work, pipes can be limited by as much as 40% of their capacity due to silt, debris, and fat burgs.

Clearing these can improve your assets operational efficiency giving you added capacity without the need for capital investment in your infrastructure.

Clear assets also reduce the risk of pollution incidents as during a storm your infrastructure is at maximum hydraulic flow meaning any blockages and the system will back-up and overflow.

We have the expertise and the equipment to repair sewerage, effluent, surface water and land drainage systems including soakaways and attenuation systems. Our all-terrain vehicles clean drainage in the most inaccessible areas.

We also have the expertise to repair complex assets such as syphons and large underground storage tanks.

Given the high profile nature of this issue you need to be seen to be taking action by your customers and stakeholders. We can support by providing case study videos for your marketing campaigns to help you maintain your hard-won reputation.

Support capital infrastructure

Planning for the next AMP cycle we have the expertise to support capital CSO infrastructure projects including:

  • In-line retention storage
  • Off-line retention storage
  • High-rate treatment
  • Sewer separation
  • Regular monitoring and inspection of assets
  • High-pressure jetting 
  • Complex syphon cleaning 
  • Asset repairs – minor tank lining repairs to complex syphon failures
  • Case study videos
  • Capital CSO infrastructure project support
High-pressure jetting

We can clean and desilt all forms of drains using a variety of high-pressure water jetting equipment and specialist attachments that remove root intrusion, silt build up, concrete deposits, bricks and grout. The matter is broken down and is then flushed through the system, to the next manhole and removed via a vacuum pump.

From van pack jetting units to high performance jet vac units, plus an ultra-high-pressure unit we have the equipment to provide a full range of services from small bore to large diameter pipework.

Our all-terrain vehicles (remote reels) allow us to clean drainage in even the most inaccessible areas, such as woodland, steep gradients and poor ground condition.

Our HGV Recycler units are the sustainable option as water is sucked up from the sewer pipe, strained of sludge and recycled.

Complex syphon cleaning

Our complex syphon cleaning services begin with a comprehensive asset inspection to evaluate the condition, access points, and potential risks.

Specialist crews – trained in supervising and carrying out high-risk, confined space entry operations – then determine the ideal isolation, drainage, and cleaning techniques for the job.

  • Pipes are isolated using bungs or gate valves. Where non-isolated pipes can’t cope with increased flow, over-pumping methods may be used to reroute excess water around the river or canal during the cleaning process.

  • Qualified professionals manage the isolation process, dealing with access chamber issues, such as corrosion on hatch boxes.

  • Once pipes are safely drained, confined space specialists gain entry via access areas on the lowest point of the syphon.

  • CCTV provides clear sight of current blockages caused by grease or debris, while highlighting snag points and fractures that could cause subsequent issues.

We then use an effective combination of leading-edge recyclers and deep suction vehicles from our nationwide fleet. Large-scale blockages are removed by powerful vacuum tankers, while environmentally friendly recyclers treat and re-use the water for jet cleaning. 

  • Deep suction tankers and recyclers clear debris, grease, and sludge, delivering a complete high-pressure clean.
  • Cracks and structural defects are repaired while the pipe is drained, adding to asset life.
  • Continuous CCTV monitoring tracks progress during the clean. 
  • Experienced project managers ensure the project remains on schedule and budget at every stage.


Assess the true category of incident

You need to ensure you have the right contracts in place to react to pollution events from your CSOs.

In a pollution event we can quickly assess the true category of incident, coordinate the wider response, and document all preventative and reactive measures taken to reduce the financial and environmental impact of the incident.

Our nationwide response team can mobilise in under two hours to respond to your emergency 24/7-365.

We can also provide aeration solutions to treat oxygen depletion in waterways caused by pollution events or algal blooms.

Read more about managing a response in the water industry in our blog here.

  • Emergency response and response contracts
  • Mechanical and chemical aeration for oxygen depletion

Keep your business compliant, safe and avoid costly downtime

Find out how Adler & Allan can identify and mitigate risk to protect your reputation, your staff and your environment

Find out how Adler & Allan can identify and mitigate risk to protect your reputation, your staff and your environment