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All for one and one for all

Northumbrian Water was given two years to install secondary sewage treatment plants. How to do it in the timescale? The answer was alliancing. Jackie Whitelaw reports.

Change of Government in 1997 meant a change of approach on a lot of things, including sewage treatment.

While the Conservatives had often encouraged the minimum option of primary treatment to meet the EU Urban Wastewater Treatment Directive, Labour had other ideas.

Labour wanted the works; primary treatment alone was not acceptable. Instead it demanded secondary treatment to reduce solid content in waste being discharged to sea to a minimum and get rid of Britain's boring tag as the dirty man of Europe.

This was all very laudable, but it left Northumbrian Water at least with a bit of a challenge.

The UWWT directive deadline is December 2000 and the finances for the extra £190M investment required by the company only came in November 1998 when the regulator allowed it to raise its prices to cover the cost.

'That left us two years to deliver secondary treatment, ' says Northumbrian Water's investment manager Alex Shaw.

The company had eight plants where primary treatment was on the way in but now it had to change tack. 'The question for us was how to manage the risk of the new work and deliver on time, ' Shaw says.

Northumbrian had been moving towards partnering, and informal arrangements had been manifesting themselves on various sites. The introduction of secondary treatment provided the impetus to make the alliances more formal.

The opportunity was there on three jobs, at Hendon, Horden and Seaham. All were on the critical path, close together on the east coast of county Durham, and Balfour Beatty's civil engineering division was contractor for the primary works on all three. As primary and secondary works would now be under construction at the same time it was decided the most productive strategy was to agree a price for the new work with the contractor already on the jobs.

So Balfour Beatty was corralled into the 'coastal partners' alliance with designer Montgomery Watson and process contractor Degremont in February last year. The team was asked to come up with a target cost for getting the jobs done by the December 2000 deadline with Northumbrian agreeing to underwrite the price of developing the target cost.

Northumbrian used the ECC option C target cost contract for its contracts with Balfour Beatty and Degremont, with payment for works based on actual cost plus a fee. 'The target cost was developed at the same time as the design and we were feeding in ideas on buildability and value engineering that would allow us to meet the deadline, ' says Balfour Beatty regional director Murray Easton.

'The big thing for us was cost certainty, ' adds Shaw. 'We did a lot of work on the identification and allocation of risk. Certainty of design, the weather and labour were all there too.'

'We talked about it a lot and it certainly helped focus everyone's minds, ' says independent cost manager for the schemes Morris Sinclair of Turner & Townsend.

The basic split in responsibility for risk was that if it was part of the target cost it was down to the contractor, and if it concerned flows and loads on the plants, then the client carried the can.

'The discussions were very useful as they gave all the partners insight into each other's difficulties, ' says Northumbrian Water project manager Dave Groark.

Closeness of the team helped in all sorts of ways, explains Montgomery Watson project manager Alan Wilson: 'Degremont gave a presentation of the treatment process to the civils side which we don't normally have.'

Critical to the success of the alliance is the incentive arrangement written into the deal. For both process and civils contracts any savings on the target cost are shared 35% with the contractor and 65% with Northumbrian Water.

Of that 65% Northumbrian keeps 35% and puts the rest into a partnering bonus pool to be shared by everyone - 25% to Degremont, 25% to Balfour Beatty, 15% for Montgomery Watson and the rest for the client. It's the extra incentive for all parties to come up with the best solution for the job, rather than for themselves.

'A cost to us might save the civils contractor a great deal more, ' explains Degremont contracts manager Shane Keaney.

'But we know we might all benefit in the end.'

'And designers have a big influence on the project - they can be conservative or not, ' adds Balfour Beatty's Easton.

'Involvement in the incentive share is encouragement to provide the most economic design.'

The risk of overspend is also catered for. 'Up to 15% we share the cost 50:50, ' Shaw says.

'Above 15% and it's the contractor's. Effectively that means we have a guaranteed maximum price 7.5% above the target cost.'

So far, the team claims, they are all on target to come in on deadline and under cost.

Working together over three sites has also brought a number of benefits. Balfour Beatty was able to persuade the designer to change the dimensions of the concrete tanks so it did not have to cut the formwork, which speeded up concreting dramatically. Tanks were the same size on all three sites too, which meant savings because the same formwork could be used.

When things were getting delayed the site team could make quick decisions. High winds at Seaham played havoc with the tower crane when the 6m deep settlement tanks were being built. 'We brought the tanks up half way and then backfilled around them and switched to crawler cranes, ' says Seaham site agent Ian Robson.

The alliance team also produced a combined programme for the three jobs so they could look at resourcing and plan out pinch points where possible.

Success of the partnering deals at Hendon, Seaham and Hordern has a bonus.

Balfour Beatty, Degremont and Montgomery Watson will be working together on the next round of Northumbrian work - the installation of UV treatment at sewage works with the aim of improving bathing water quality.

The works

Treatment process is the same for all the works. Primary treatment required construction of fine screen inlets to remove grit, lamella tanks to separate water and solids, picket fence thickener tanks to thicken the solids and sludge holding tanks.

'Cleaned' water is sent out to sea via outfalls.

Secondary treatment - the biological process where bacteria and micro organisms feed on the substances in the water - meant the addition of aeration tanks (to provide oxygen to allow feeding bacteria to grow) and circular settlement tanks to split out clean water and solids. The resulting sludge is returned to the holding tanks and cleaned water is pushed into the sea through outfalls.

Sludge is collected by tanker from Seaham and Horden, and is stored at Hendon before being taken by sea to Northumbrian Water's sludge reprocessing plant at Bran Sands (NCE 28 January 1999).

Hendon has three week's storage capacity.

Primary treatment removes around 50% of solids contained in untreated sewage.

Secondary treatment removes a further 45%.

Similarly primary treatment removes 20% of biological oxygen demand (BOD) - the measure of the polluting load in the untreated sewage.

Secondary treatment removes a further 70%.

On the spot

Name: Ian Robson

Age: 37

Qualifications: HND in civil engineering

Current job: Site agent, Seaham WWTW for Balfour Beatty Civil Engineering

Best thing about current job:

Being able to influence the designs to improve buildability. For instance, persuading our designers to change the dimensions of the aeration lanes so we didn't have to cut any shuttering.

Worst job: Suddenly finding myself in charge of rail welding for gantry cranes at a container port in Dubai.

I ended up faxing the technical department of the Belgian welding rod supplier for advice. No one there spoke English so I would send a question, they would get it translated, answer it, translate it into English and fax it back to me.

This went on for three months.

Anything else: I believe in Father Christmas again after I met him in Lapland.

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