Work has begun on a £400m incinerator at an ex-airbase that will take in 600,000 tonnes of rubbish each year.
Permission to build the facility, with a 35m (114ft) high chimney at Rivenhall, near Braintree, Essex, was granted last year.
Indaver, the firm behind it, said it was "more environmentally friendly than landfill".
Critics of the project said they were worried about the environmental impact and that the chimney was too short.
The incinerator is due to open in 2025 and will take waste from Essex and surrounding counties, although no agreement has yet been reached with Essex County Council.
Plans for the facility had been granted permission in 2010 but it required a permit to operate from the Environment Agency, which was given last year.
Gareth Jones, from Indaver who will operate the facility with Gent Fairhead and Co, said: "Waste that goes into landfill tends to degrade and it produces methane, which is a greenhouse gas.
"Although the waste here will be converted to carbon dioxide, that's still less damaging to the atmosphere."
He added the plant would be "burning non-hazardous waste".
Nick Unsworth, from Parishes Against Incineration, said the plant would produce "poor air quality" and 200,000 tonnes of bottom ash or non-combustible residue.
"It will turn Essex into the country's ashtray," he added.
Witham MP and Home Secretary Priti Patel said she "supports the concerns of local residents" over the incinerator.