There's a system for treating sewage, based on a model made from cereal packets, tubes and wire and held together with glue and sticky tape.

This system will bring cleaner seas to Shoreham, Southwick and Hove.

Southern Water engineer David de Hoxar invented the spiral separators as a way of saving space and money at treatment plants.

Following a £2 million development programme by the company, the invention is now beginning its life in industry and the installation at Shoreham is one of several along the South Coast.

The system is deceptively simple using giant plastic fins formed into interlocking spirals in the treatment tank.

As the spirals rotate solid waste in the sewage settles out on the fins and drops to the bottom of the tank where it is removed as sludge for recycling into organic fertiliser.

Mr de Hoxar, who is based at Falmer, said: "The system is far more compact than conventional methods of carrying out this type of sewage treatment.

"The spirals take up only a fraction of the space, making them ideal for restricted sites like the one at Shoreham.

"I originally came up with the idea 15 years ago and it is very satisfying to see the hard work that has gone into developing it finally starting to pay off."

The spirals at the Shoreham works, in Basin Road South, are part of an £11 million scheme to bring further improvements in water quality, in line with European environmental standards.

They will begin treating their first flows later this year and become fully operational in 2002.