Concerns have been raised over a housebuilder’s bid to dump more than 900,000 litres of sewage effluent into a tributary of a protected river every day.

Hodson Developments is building a wastewater treatment plant which will eventually serve almost 3,000 new homes at the huge Chilmington Green “garden town” in Shadoxhurst, near Ashford.

Now the London-based firm has applied to the Environment Agency (EA) for a permit to discharge the effluent into a stream that flows into the River Beult - a Site of Special Scientific Interest (SSSI).

Hodson insists “stringent measures” will be in place to ensure no harm is caused “to local habitats and the local populace”.

The discharge point would be 10km upstream of the River Beult, a “delicate and vital ecosystem” home to rare habitats and species - including aquatic plants, invertebrates and fish.

Hodson has applied to dump almost 1,000 cubic metres of treated wastewater from the plant every day, which would fill about three 25-metre swimming pools.

Bethersden parish councillor Alastair Boyd fears the river could be damaged beyond repair.

“There is not sufficient water going down to make a flow, and so if you add the amount they’re looking for, it will be in pools along the river, and I don’t know what the impact will be on the environment,” he said.

“And when there are heavy rains, and it floods, all those contaminants will go out on agricultural land and people’s gardens.”

Problems relating to the impact of wastewater on the Stodmarsh Nature Reserve near Canterbury prevented Chilmington Green’s developers from using an existing Southern Water facility.

Natural England rules insist housebuilders must ensure all schemes in the River Stour catchment area - stretching between Ashford, Canterbury and Hawkinge - are “nutrient neutral”.

This means developers must either install an on-site water treatment facility or offset the impact by providing mitigation measures elsewhere, such as wetlands.

Hodson’s initial plans to build a sewage treatment plant was originally refused by Ashford Borough Council due to fears of “intolerable odours” - but this was overturned on appeal.

Cllr Boyd questions why the River Beult is not being offered the same protections as Stodmarsh.

He said: “If the water coming out of the Ashford works is not suitable for the River Stour, how can it be right to put the same water into the River Beult, which is also an SSSI, and mess that up as well?

“The problem is the present government is desperate for houses, and the only way they can get the Chilmington job going again is to muck up the Beult, but that runs right the way through to the River Medway, and there’s a lot of areas through there which are SSSIs.”

Hodson will be responsible for 700 homes at Chilmington Green in the first phase and a total of 2,700 in the second. In total, the estate will eventually grow to 6,000 homes.

For work to start on the treatment plant, the firm must obtain an environmental permit from the EA.

An environment assessment submitted by Wardell Armstrong on behalf of the applicants says: “Stringent control measures, maintenance and monitoring will be employed on-site to ensure that there will be no harm caused to local habitats and the local populace through site activities.

“If pollution is detected or an incident occurs, the Environment Agency will be contacted.”

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The EA told KentOnline a permit would only be issued if the applicant demonstrates the site can operate and fully comply with all legal and environmental requirements.

Even if permission is granted, it will continue to monitor compliance through regular inspections.

A spokesperson said: “We carefully review all permit applications to ensure they meet stringent environmental, technological, and health requirements before deciding whether to grant them.

“An environmental permit sets out specific conditions a site operator must follow to protect the environment.

“We only grant a permit if we are confident these conditions will be met.

“If granted, we conduct periodic audits and inspections to ensure the permit holder continues to comply with these requirements.”

The Kent Wildlife Trust is urging the EA to reject the request for the permit.

A statement on the charity’s website says the River Beult “faces severe ecological threats” from the proposals.

“This fragile ecosystem could suffer from nutrient pollution, untreated sewage during floods, and contamination affecting livestock and farmland,” it says.

“The Environment Agency must act to protect this vital habitat and prevent long-term environmental damage.”

Hodson Developments has been contacted for comment.

It comes after concerns were raised over the firm’s bid to pull out of contributing more than £50 million worth of new infrastructure and community facilities - including a £30 million major road improvement.

The housebuilder has thrown into doubt the future of the A28 dualling project after seeking to discharge or delay several obligations under the Section 106 agreement it signed in 2017.

Hodson has applied to the Planning Inspectorate to determine its application to vary 33 conditions of the 5,750-home Chilmington Green development.