More than 1,000 tonnes of waste was disposed of on unlicensed farmland near Padstow in north Cornwall over at least a year up to January 2003.
Treveglos Farm owner Richard Bennett was fined £10,000 for depositing waste on unlicensed land and £2,500 for keeping controlled waste on unlicensed land. His son, Ernest Bennett, was fined £5,000 for depositing waste on unlicensed land.
Contractor Steven OHagan, who worked for the Bennetts as a tractor driver, was given a two-year conditional discharge after dumping and compacting around two-thirds of the waste.
Builder Andrew Pitt of Trevone also received a two-year conditional discharge for failing to provide a written description of waste he passed to the Bennetts for disposal. And fellow builder Phillip Canfield was fined £500 for not ensuring waste was properly disposed of.
Magistrates at Launceston last week handed out the punishments after watching video footage taken by agency officers in January 2003.
The farm lies just 100 metres from the main road between Newquay and Padstow yet the illegal activities were hidden.
Around 100 trailer-loads of dumped material were compacted between two bunds, lying in water.
This waste included asbestos, rubble, television sets, packaging, metal, cardboard, plastic, roofing felt, ceramics and plastics.
The Bennetts were charging between £30 and £48 per tonne to take the waste.