Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Wastewater: Water channels its cash into key assets

Although there are still two years to go before the start of the next asset management plan (AMP) period in the water sector, the industry is already looking ahead to 2015, and eyeing up the prospects for AMP6.


Investment flow: The vast Beckton sewage treatment works is currently being upgraded

Each new AMP round is an opportunity for the industry to develop innovation in response to regulator Ofwat’s latest demands and the requirements of new legislation, but this time round the supply chain is anticipating that the water companies will be looking for something very different, as the focus shifts away from delivering massive capital projects and towards improving operational efficiency.

The UK water industry is understandably proud that, since it was privatised in 1989, it has invested more than £90bn to replace and upgrade an asset base that, in some instances, was more than 100 years old. This capital investment programme has been driven both by the need to reduce the cost of supply, and by legislation - much of it from Europe - to clean up the effluent being discharged at the end of the treatment process.

With much of this work now complete, the industry is shifting its focus towards operating, maintaining and managing these assets. It is a shift that started during the current asset management period, AMP5, with cost consultant EC Harris calculating that around £19bn of spending in AMP5 has been on operational asset management compared with £24bn on capital works. But in AMP6, operational expenditure could take the bulk of the money for the first time.

“We are currently in year three of AMP5, and this AMP is a bit of a transition,” explains Siltbuster Process Solutions technical manager Chris Bullen. “Historically, a lot of the work has been quality led in order to meet European legislation - particularly discharge legislation such as the urban wastewater treatment directive.

“We are now starting to see projects that are driven by capital maintenance requirements, which is being led by Ofwat’s emphasis on ensuring customers are getting value for money.”


“We are now seeing projects that are driven by capital maintenance requirements”

Chris Bullen, Siltbuster Process Solutions

Ofwat is also keen to see water companies meet tough serviceability requirements - which means they are faced with the challenge of carrying out maintenance and improvements to their assets without adversely impacting the level of service they provide to their customers. New regulatory rules shift the way the companies’ performance is measured from an output-based mechanism to a more customer-focused mechanism, so water companies will have to clearlydemonstrate that the money they spend will bring benefits to customers.

“Historically, a lot of the work has been quality led in order to meet European legislation”

Chris Bullen, Siltbuster Process Solutions

“Early in this AMP you saw a lot of feasibility work being done, and then you saw the water companies switching to monitoring their serviceability levels to ensure they are being met,” explains Bullen. “Poor maintenance threatens serviceability.”

The combination of Ofwat’s twin-pronged approach of serviceability and value for money is set to result in a more risk-based approach, according to Bullen, with water companies spending more time and money monitoring their assets so they can prioritise their workload. “Each company will have a central risk register, with a cost associated with each risk, so they can work out where they will get the most for their money,” he explains.

Over the next 12 months contractors and consultants will have to work out how to adapt to these changed priorities. For the last 20 years, the skills the water companies have valued have been mainly in the design and construction of new works - often massive projects with scope for value engineering and collaborative working to reduce costs and improve efficiency. Now they will, increasingly, be looking for help in optimising maintenance regimes, finding efficiencies in smaller upgrade projects and developing innovative ways to keep existing works running while essential maintenance takes place.

Bullen says his company - which supplies mobile treatment units - is getting an increasing number of calls from water companies that are looking for an alternative to the traditional methodology of building spare capacity at their works just so they are covered when an element has to be taken off-line for maintenance, or is only used during rare periods of high flow. “If you look at it from a serviceability standpoint, which requires you to spend money where it will improve the service to customers, then there is a big question over whether you should be spending a lot of money on a settlement tank that’s only going to be used for 10 weeks of the year,” he says.

£19bn The amount of AMP5 cash spent on operational assets according to EC Harris

£90bn The amount the UK water industry has spent since 1989 upgrading assets

Historically, water companies’ operational standards for treatment works have often required a level of redundancy to ensure they can remain operational if there is a problem - so you might get two final settlement tanks when normal daily operations only require one. Bullen says the new risk-based approach is likely to make them rethink this strategy, especially if temporary alternatives are available.

While Ofwat is pushing water companies to focus on value for money and serviceability, they certainly cannot afford to take their eye off the ball as far as quality standards are concerned - especially the urban wastewater directive, which is the main driver behind projects like Thames Water’s proposed Tideway Tunnel and major interceptor sewers throughout the country, such as those currently being built in Scarborough and Preston. The European Commission is likely to come down hard on countries that breach the discharge standards outlined in the directive, and urban UK’s reliance on combined sewers means any heavy rainfall event can result in the sewer network overflowing, and untreated discharge getting into rivers.

“The key to meeting the legislation is capturing storm water,” explains Bullen. “The directive says you have to manage these flows, so it could potentially lead to some very big storm water storage systems being built.”

NCE infrastructure 2013


Filling a gap: Temporary wastewater treatment plant

Siltbuster Process Solutions (SPS) has been working with a number of the UK’s water companies to provide a range of different temporary and permanent packaged treatment plants, including dissolved air flotation (DAF), submerged aerated filter (SAF) and lamella clarifiers. The temporary units have been used for a variety of reasons, including to improve site compliance, reduce operational costs and enable maintenance and upgrade work to be undertaken.

In a recent example, a water company needed to undertake maintenance on a single stream packaged activated sludge plant, but had been unable to undertake the work as there was no means of diverting the flow from the site. Operational and compliance risk was increasing as remedial works were delayed, and tankering was not a viable option.

SPS came up with a solution to divert the flows to a temporary wastewater treatment works consisting of one mobile lamella primary settlement tank, two mobile SAF units and one mobile lamella humus settlement tank.

The packaged design of equipment and the use of temporary above ground pipework enabled the equipment to be set up quickly on a hard standing that had been prepared by the water company prior to SPS’s arrival on site.

After a short period of acclimatisation, discharge from the mobile plant was compliant, and could be diverted to a watercourse.

The water company was then able to decommission the activated sludge plant and review its maintenance needs, while taking a long term planning approach to the site.

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.