A father and son from Buckinghamshire have been convicted after being caught setting fire to rubbish at a farm near Amersham.
An investigation by the Environment Agency found David and Nicholas Channer "continually put the environment at risk" by burning wood, metal and waste at the farm in Mop End.
Burning rubbish is a cheaper alternative to authorised disposal.
The pair continued despite "countless" letters and visits, between 2017 and 2019, from environmental crime investigators.
Watch the moment environmental crime investigators found rubbish alight at the farm:
Smoke with a chemical odour caused an Environment Agency officer’s eyes to sting.
Mounds of smouldering ash were found from the incinerated rubbish.
David Channer admitted burning waste collected from elsewhere, leading district judge Malcolm Dodds to say the 67-year-old was “pig-headed” for not responding to “plentiful warnings” from the Environment Agency.
David Channer received a six-month jail term, suspended for two years.
DJ Dodds said David Channer took no steps to limit the effect of his son’s tree maintenance firm as the illegal rubbish built up.
Nicholas Channer managed Chiltern Tree Care, based at the farm. The operation created significant amounts of waste that should have been disposed of legally.
The 47-year-old was already subject to a suspended prison sentence for unrelated matters at the time of these offences.
Nicholas Channer was jailed for five months, on top of the eight months for waste crime.
Charlotte Milton, a senior environmental crime officer for the Environment Agency, said: "David and Nicholas Channer have been rightly punished by the courts for riding roughshod over the law around managing waste safely and securely.
"The men had no system in place to limit the amount or type of waste held at Mop End Farm, nor did they establish measures to protect the environment or human health. The law requires anyone dealing with waste to keep it safe, make sure it’s handled responsibly, and only given to businesses authorised to take it."
When asked to explain their actions, the Channers told the Environment Agency they either had not seen letters from crime officers, or were unaware exemptions from permits for managing the waste had expired.
Nicholas Channer confessed to holding 100 tons of scrap metal at the farm, which he obtained from online customers or by driving around looking for it.
While the areas where the fires took place have been partially cleared, David Channer, as landowner, has until December this year to remove the remaining contaminated ash.
As well as his suspended prison term, David Channer was ordered by High Wycombe Magistrates’ Court to pay the Environment Agency’s full costs of £14,925, and a £115 victim surcharge.
In a separate hearing at Aylesbury Crown Court, in addition to his custodial sentence, Nicholas Channer was fined £40,000, with full costs of £15,122.45, and a victim surcharge of £140.
The pair were prosecuted eight years ago for committing similar offences.