Northumbrian Water is to provide bug-busting ultra-violet light treatment at five of its largest sewage works as part of a �700m programme of coastal improvements.

Equipment already installed in one centre, should be operational in time for the 2002 bathing season.

The five additional sewage treatment works to receive the lighting system, at a total of almost �13m, are Howdon on Tyneside, Hendon on Wearside, Billingham, Bran Sands and Marske in Teesside.

Any bacteria and viruses remaining in treated water after the initial sewage processes are exposed to intense UV radiation, and are rendered inactive.

'Protect' waters

The decision will be announced on Wednesday at the company's Seaton Carew sewage treatment works in Hartlepool, location of the first UV disinfection plant in the region.

The utility says the new plant will help protect the North East's bathing waters.

Following the commissioning of 11 new secondary treatment works at the end of 2000, the water reached its highest-ever standard during the 2001 bathing season.

All of the 32 waters achieved the mandatory standard and 24 of them also achieved the much stricter guideline standard.

Northumbrian Water chairman, Sir Fred Holliday, will sign contracts with civil engineering firm Byzak Contractors Ltd and Wedeco UV Systems Ltd to help create the new systems.

A Northumbrian Water spokesman said: "Ultra-violet light disinfection is a tertiary sewage treatment process - it follows preliminary, primary and secondary treatment.

Tube works

"It works by passing the secondary treated water through a covered channel, into which are suspended banks of UV tubes, parallel to the direction of flow.

"The tubes emit light at the ultra-violet end of the spectrum.

"As the water passes the tubes, any bacteria and viruses remaining in the water are exposed to intense UV radiation and are rendered inactive."

A total of 5,800 UV tubes, similar to fluorescent light tubes, will be used at the six works. Of these, more than 2,500 will be used at Howdon, almost 2,000 at Bran Sands and 650 at Hendon.

Northumbrian Water is waiting for the outcome of a public inquiry held in Sunderland in October over an application to discharge overflows from its sewerage system into the North Sea.

The firm has applied for permission to use the outlets in the quay wall at Whitburn and the outfall pipe at its new �70m sewage treatment works in Hendon.

The company says it only uses the two outfall pipes in emergencies and is applying to make their use more regular.

But campaigners claim Northumbrian Water already discharges effluent more often than it says it does and that it is damaging the environment.

A ruling is expected in January, which will then go to Secretary of State Margaret Beckett for a final decision.