Residents are fighting plans to build a sewage treatment plant in a wildlife haven.

They fear discharge released into the Bevern Stream at South Chailey, near Lewes, will harm fish and insects and eventually pollute the Ouse River.

Lloyds Environmental Waste Management has asked the Environment Agency for permission to release up to 300 cubic metres a day of processed sewage, food waste and oil products into the Bevern Stream via a ditch.

The company says the waste will be treated to a high standard at the Hamsey Brickworks plant and diluted in a lake and there will be no adverse effects on the environment.

But 60 residents, conservationists and councils have written to the Environment Agency to object to the scheme, which they say will destroy the tranquil spot and cause a huge increase in traffic.

At present, the Hamsey Brickworks site is used by the company to transport sewage, farm effluent and oily water for treatment elsewhere.

Martin Mulholland, chairman of Sussex Ouse Conservation Society, said: "Our own surveys have shown the Bevern Stream is a key place for rare sea trout to spawn and breed. There is a rich diversity of wildlife such as dragonflies, butterflies and kingfishers.

"If they release food waste into the water this will reduce the amount of oxygen and kill the fish. Even if the discharge is treated well, mistakes are always made and there are sudden bursts of untreated sewage. That is murder for fish.

"There is never much water in the stream and if they are releasing 300 cubic metres the effect will be dire.

"There must be other sites for dealing with this."

Paul Segal, managing director of Lloyds Environmental Waste Management, said the scheme complied with council guidelines which state waste should be treated within the county.

He said: "Our application for consent to discharge is based on a significant investment in the most modern and effective plant which is guaranteed by leading manufacturers to protect our own property and the wider environment.

"The treated water from the plant will have no smell and will meet very stringent quality standards which will be continuously monitored both by ourselves and the Environment Agency."

Mr Segal said the discharge released into the stream would probably be cleaner than the water in it and there would be no damage to wildlife.

He said there would be fewer traffic movements because the waste would be treated locally.

The public has until Thursday to make its views known to the Environment Agency and a decision will be taken in October. The development will then have to go through the council planning process.

An Environment Agency spokeswoman said consultation was being carried out with external groups to find out if the plan would harm the environment.