Southern Water says the work is needed to meet EU standards

The firm says the plan means improved environmental treatments and cleaner sea water off the Sussex coast.

But surfer groups claim it offers secondary, not full, water treatment and water could contain faecal bugs.

On Thursday the firm will apply to both East Sussex County Council and Brighton city council for planning permission.

Pumping stations

The plan also includes a 11km (6.8 miles) long underground sewer between Black Rock and Peacehaven, to transfer waste water to the new works.

Underground pumping stations and underground shafts will also be built in Brighton.

The company, which says the new scheme is needed to meet EU directives, plans to hold a public exhibition to update local residents on its proposals.

But some Peacehaven residents are angry at the plans and claim the area is being used to deal with Brighton and Hove's sewage.

They fear it will smell and blight the countryside but the water firm says foul air will be extracted and the plant will have environmental benefits.

Earlier in March Richard Gregory, of Surfers Against Sewage, said: "Both councils should adopt a policy that best reflects the needs of local people, the environment and recreational water users and that's full sewage treatment, not secondary."